Friday, September 26, 2014
DC Voltage Doubler Circuit Explained
- The inverters, N3. . . N6, are connected in parallel and operate as a buffer stage to reduce the load- dependence of the circuit.
- Depending on the clock signal of the oscillator, point A in figure 1a is connected to the earth rail for a particular time per period and to the supply voltage for a particular time.
- This causes the voltage across capacitor C2 to rise to almost twice the supply voltage. If D1 is connected to earth and the -polarities of diodes D1, D2 and capacitors C1, C2 (figure 1b) are reversed, the output at A will be a negative voltage and, in the no load condition, it will be at the same level as the supply voltage.
- In both cases, unfortunately, the output voltage is dependent upon the load. As the load increases, the output voltage drops; in contrast, the superimposed a.c. level rises. The table shows the values measured in the circuit for load currents of 5 mA and 15mA.
- This simple circuit can produce a d.c. voltage which is approximately twice the supply voltage, in the no- load condition.
- Whilst point A is connected to earth, capacitors C1 and C2 charge up to the supply voltage via diodes D1 and D2. The oscillator then switches point A to the supply voltage potential during the remaining period, capacitor C1 transfers a part of its charge to capacitor C2.
- The 4049 IC contains a total of six inverters. Two of them, N1 and N2, form an oscillator together with R1 and C3, of which the frequency is about 10 kHz.
How to Charge a Lead Acid Battery Circuit Diagram
- Batteries should not be discharged below 1.8 volts per cell, as it can cause permanent damage to the cells.
- A 40 ampere-hour battery when discharged at 4—ampere rate will take 40/ 4, i.e. 10 hours to be completely discharged. Suppose the same battery is discharged at 10—amperes rate. Theoretically, it should take 40/ 10, i.e. 4 hours to get fully discharged. But in practice it 1S observed that the battery will get fully discharged within about 3% hours itself In other words, the higher the discharge rate, the lesser will become the capacity of the battery.
- A fully discharged battery needs to be charged about 1% times its full ‘capacity’, to reach a fully charged, state. In other words, a 40-AH battery being charged at 4 amperes rate will take 15 hours and not 10 hours to be fully charged Charging a partially discharged battery =· It is not possible to estimate the time needed to charge a partially discharged battery.
- The charging or discharging of a battery is ideal at 10 hours rate, which means that a 40 ampere hour battery is to be charged or discharged at 40/ 10, i.e. 4-ampere rate.
- Lead—acid battery has a voltage of 2.1 volts per cell (on load) when fully charged, which will rise up to 2.7 volts per cell while on charge. When the voltage per cell (on load) drops to 1.8 volts, the battery is considered to be fully discharged.
- However, the battery may be charged till such time as the following are observed: (a) Free gassing of the cells. (b) Battery voltage reaches its maximum value, and remains steady. (c) The specific gravity of the electrolyte (as measured by a hydrometer) reaches 1.240
- That’s why is engine starting, when the battery drains 200 to 300 amperes, the battery becomes dead’ within a few seconds of use.
Thursday, September 25, 2014
Track and Hold Circuits Explained
Track and hold circuit using FET
When the switch is closed (or the FET conducting), circuit is behaving as an inverting amplifier with a gain of L?. As the inverting terminal of the op amp is a virtual earth, the capacitor is kept charged to the output voltage by the op amp.
When the 3 switch is opened (and the FET non- Q conducting) the voltage at the output is held constant by the capacitor, the current demands of the next stage being met by the op amp. Note that the value of C should be chosen such that its impedance at the operating frequency is. large compared to R1 and R2.
Track and hold circuit using opamps
When the control input is high the output tracks the input but when it goes low the output remains frozen at the value it was at the instant of transition. The operation of the circuit is generally self-evident and it may be regarded as two voltage followers, one consisting of two o- amps with the output following the input, the other is just the second op—amp which "foIlows" the voltage stored on the capacitor. lt is advisable to take care with the layout as with all op—amp circuits due to the huge open loop gain of these devices. The value chosen for C is a compromise between "siewing rate," that is the rate at which the circuit tracks a sudden change of input and "holding ability" which is the length of time, the circuit will hold a signal without unreasonable decay. To give some sort of guide, for a 10kHz square wave to the control input, a 0.01 p F capacitor seems to optimize the performance. The value of the resistors is also worth experimenting with.
When the switch is closed (or the FET conducting), circuit is behaving as an inverting amplifier with a gain of L?. As the inverting terminal of the op amp is a virtual earth, the capacitor is kept charged to the output voltage by the op amp.
When the 3 switch is opened (and the FET non- Q conducting) the voltage at the output is held constant by the capacitor, the current demands of the next stage being met by the op amp. Note that the value of C should be chosen such that its impedance at the operating frequency is. large compared to R1 and R2.
When the control input is high the output tracks the input but when it goes low the output remains frozen at the value it was at the instant of transition. The operation of the circuit is generally self-evident and it may be regarded as two voltage followers, one consisting of two o- amps with the output following the input, the other is just the second op—amp which "foIlows" the voltage stored on the capacitor. lt is advisable to take care with the layout as with all op—amp circuits due to the huge open loop gain of these devices. The value chosen for C is a compromise between "siewing rate," that is the rate at which the circuit tracks a sudden change of input and "holding ability" which is the length of time, the circuit will hold a signal without unreasonable decay. To give some sort of guide, for a 10kHz square wave to the control input, a 0.01 p F capacitor seems to optimize the performance. The value of the resistors is also worth experimenting with.
Power Back up Circuit for CMOS ICs
Even very brief mains power failures cause problems for electronic circuits. Stored data are lost and the operating statuses are no longer what they were before the power failure.
Mains power failures cannot be prevented, but methods can be employed to provide a voltage backup for the duration of the fault. For this reason, mains-powered equipment is often fitted with backup batteries (nicad or lithium cells) to maintain operation during a mains power failure. In view of the low currents (microamperes) required for data storage with modern Fl/-lVls, there ls·~ an alternative backup method which is well worth consider- ing: power backup with an electro- lytic capacitor for energy storage! The circuit diagram Tshcvvs .just such an application. The power standby’ capacitor C1 is 4700 ;,iF and with a maximum load current of 10;;/~, the discharge time at an output voltage of 5 V is approxi- mately 53 minutes. The operating voltage of the circuit itself is 15 V, 10 V higher than the output voltage. As long as the 15 V supply voltage ls applied, capacitor C1 charges up to the value of the operating voltage via diode D1. Simultaneously, a bias voltage of approximately 2.3 V is applied to the gate of field effect transistor T1 via voltage divider R1/R2. This ensures that T1 is turned on and capacitor C2 is charged up.
The output voltage at the source t iinal r~· th e second field effect transistor remains a constant 5 V. The two FETs can be thought of as a voltage divider. lf the supply voltage fails, electro- lytic capacitor C1 will become the temporary power supply. Since the gate voltage is removed from T1 it turns off. Capacitor C2 is no longer being charged. However, it‘can only discharge very slowly because T2 has a very high input resistance. The voltage across C2 remains almost constant. Capacitor C1 supplies the operating voltage required for T2 so that it conducts and maintains the output voltage at 5 V. Capacitor Cl discharges very slowly, as a function of its insulation resistance (R|N3 approximately 1 l/ll and the load current flowing. The output voltage at the source lead of T2 remains a constant 5 V, until the voltage across C1 has also dropped to 5 V. lf this voltage drops even further, FET T2 remains turned on but the output voltage decreases proportionally. For correct functioning of the circuit, it is very important t0 select an MKT type of foil capacitor for C2. (M stands for metailised and KT is the standard designation for pciyester foii). (Siemens Application}
Mains power failures cannot be prevented, but methods can be employed to provide a voltage backup for the duration of the fault. For this reason, mains-powered equipment is often fitted with backup batteries (nicad or lithium cells) to maintain operation during a mains power failure. In view of the low currents (microamperes) required for data storage with modern Fl/-lVls, there ls·~ an alternative backup method which is well worth consider- ing: power backup with an electro- lytic capacitor for energy storage! The circuit diagram Tshcvvs .just such an application. The power standby’ capacitor C1 is 4700 ;,iF and with a maximum load current of 10;;/~, the discharge time at an output voltage of 5 V is approxi- mately 53 minutes. The operating voltage of the circuit itself is 15 V, 10 V higher than the output voltage. As long as the 15 V supply voltage ls applied, capacitor C1 charges up to the value of the operating voltage via diode D1. Simultaneously, a bias voltage of approximately 2.3 V is applied to the gate of field effect transistor T1 via voltage divider R1/R2. This ensures that T1 is turned on and capacitor C2 is charged up.
The output voltage at the source t iinal r~· th e second field effect transistor remains a constant 5 V. The two FETs can be thought of as a voltage divider. lf the supply voltage fails, electro- lytic capacitor C1 will become the temporary power supply. Since the gate voltage is removed from T1 it turns off. Capacitor C2 is no longer being charged. However, it‘can only discharge very slowly because T2 has a very high input resistance. The voltage across C2 remains almost constant. Capacitor C1 supplies the operating voltage required for T2 so that it conducts and maintains the output voltage at 5 V. Capacitor Cl discharges very slowly, as a function of its insulation resistance (R|N3 approximately 1 l/ll and the load current flowing. The output voltage at the source lead of T2 remains a constant 5 V, until the voltage across C1 has also dropped to 5 V. lf this voltage drops even further, FET T2 remains turned on but the output voltage decreases proportionally. For correct functioning of the circuit, it is very important t0 select an MKT type of foil capacitor for C2. (M stands for metailised and KT is the standard designation for pciyester foii). (Siemens Application}
Digital Clock Circuit Diagram
The complete circuit diagram is shown in Fig. 1. Heart of the system is lC2, National’s MM5402 clock chip. It is an MOS monolithic large scale integrated circuit.
Its pin configuration is shown in Fig. 2. The supply is derived from the mains through a low-voltage stepdown transformerXl . As shown in the diagram, 9-volt DC supply derived by diode D3 and capacitor Cl is fed to the counting circuit of the clock chip at pin 29 through a lk resistor. A bypass capacitor C5 is used at r input of clock chip for protection from high-frequency transients. The current requirement for the entire clock chip is around 4.5 mA. . The clock input pin 35 is fed by 60Hz clocked pulses. These are derived by 3.579 MHz quartz crystal oscillator formed with ICI, Nationals MM5369 chip, which is also ia frequency divider. Its output at pin I is 60Hz square wave For trimming the crystal frequency, a trimmer (C4) is also provided which could be used for improving the accuracy of time. For display, Fairchild’s FNDSOO seven-segment light emitting diodes (LEDs), D7 to D10, are used. These are common-cathode LEDs.
Since the clock chip’s segment output is of the order of lO mA, no interfacing is required. The various LED segments are only to be connected to the respective clock outputs. In all, four LED displays are required, and these can be straightaway soldered on to a separate PCB or breadboard. Supply to the display LED is obtained from the 3V tap of transformer Xl. The pin configuration of FND500 is shown in Fig. 3. The blinking colon is also available in the FND500 display.
It is provided at pin 5 of the display, and may be connected through a 220-ohm current limiting resistor to pin 39 of the clock chip. The a.m. and pm. displays are obtained by using two LED lamps, D5 and D6, and connected to pins I and 40 of clock chip through 220-ohm current limiting resistances. All the U’Eplay functions are obtained by simply connecting push-button switches at various control inputs, and grounding the respective input. In the prototype a self- assembled seven-reed assembly of switches was used. However,though costlier, the miniature calculator keyboard switches made by O/E/N India Ltd are the best for this purpose. Alarm output is available at pin 25 of the clock chip. Since this output is quite low, a current driver is used.
This driver is formed by the transistor Tl and a few supporting components, as shown. Fora gentle alarm sound, tone is generated by lC3, which is an Indian timer IC 555. The tone can be varied by changing the value of capacitor C7. An 8—ohm, 0.5- watt speaker of 6.3 cm dia should produce sufficient sound to be heard across the room. _ The sleep output at pin 27 of the clock chip is similarly amplified and used to drive a relay which can control any audio or electrical equipment. The function of sleep timer is to switch off a radio set, tape recorder, TV etc after a preset time, within the maximum duration of 59 minutes.
Since the clock chip as well as the crystal oscillator-cum- divider IC operate on 9V supply (actual operating range : 7 to ll volt), a battery back—up system can be used to keep the clock running during mains failure. There will be no display of time while the clock is running on this back-up system, but on the resumption of power through AC mains the clock will automatically display the correct time. lf due to any reason supply to the clock chip is cut off, all the digits will flash at lHz to indicate that time displayed is incorrect.
Its pin configuration is shown in Fig. 2. The supply is derived from the mains through a low-voltage stepdown transformerXl . As shown in the diagram, 9-volt DC supply derived by diode D3 and capacitor Cl is fed to the counting circuit of the clock chip at pin 29 through a lk resistor. A bypass capacitor C5 is used at r input of clock chip for protection from high-frequency transients. The current requirement for the entire clock chip is around 4.5 mA. . The clock input pin 35 is fed by 60Hz clocked pulses. These are derived by 3.579 MHz quartz crystal oscillator formed with ICI, Nationals MM5369 chip, which is also ia frequency divider. Its output at pin I is 60Hz square wave For trimming the crystal frequency, a trimmer (C4) is also provided which could be used for improving the accuracy of time. For display, Fairchild’s FNDSOO seven-segment light emitting diodes (LEDs), D7 to D10, are used. These are common-cathode LEDs.
Since the clock chip’s segment output is of the order of lO mA, no interfacing is required. The various LED segments are only to be connected to the respective clock outputs. In all, four LED displays are required, and these can be straightaway soldered on to a separate PCB or breadboard. Supply to the display LED is obtained from the 3V tap of transformer Xl. The pin configuration of FND500 is shown in Fig. 3. The blinking colon is also available in the FND500 display.
It is provided at pin 5 of the display, and may be connected through a 220-ohm current limiting resistor to pin 39 of the clock chip. The a.m. and pm. displays are obtained by using two LED lamps, D5 and D6, and connected to pins I and 40 of clock chip through 220-ohm current limiting resistances. All the U’Eplay functions are obtained by simply connecting push-button switches at various control inputs, and grounding the respective input. In the prototype a self- assembled seven-reed assembly of switches was used. However,though costlier, the miniature calculator keyboard switches made by O/E/N India Ltd are the best for this purpose. Alarm output is available at pin 25 of the clock chip. Since this output is quite low, a current driver is used.
This driver is formed by the transistor Tl and a few supporting components, as shown. Fora gentle alarm sound, tone is generated by lC3, which is an Indian timer IC 555. The tone can be varied by changing the value of capacitor C7. An 8—ohm, 0.5- watt speaker of 6.3 cm dia should produce sufficient sound to be heard across the room. _ The sleep output at pin 27 of the clock chip is similarly amplified and used to drive a relay which can control any audio or electrical equipment. The function of sleep timer is to switch off a radio set, tape recorder, TV etc after a preset time, within the maximum duration of 59 minutes.
Since the clock chip as well as the crystal oscillator-cum- divider IC operate on 9V supply (actual operating range : 7 to ll volt), a battery back—up system can be used to keep the clock running during mains failure. There will be no display of time while the clock is running on this back-up system, but on the resumption of power through AC mains the clock will automatically display the correct time. lf due to any reason supply to the clock chip is cut off, all the digits will flash at lHz to indicate that time displayed is incorrect.
Wednesday, September 24, 2014
Triangular wave form Generator Circuit
A triangular waveform generator can Vi be made by using one amplifier of a LM3900N device as an integrator and another amplifier as a Schmitt trigger circuit.
A suitable circuit is shown, it has the unusual advantage that only the one power supply is required. When the output voltage from the Schmitt trigger circuit is low, the current flowing through Ra is integrated by C; to produce the negative slope of the triangular wave at output 1. When the output 2 voltage from the Schmitt trigger ls high, current flows through R; to produce the rising part of the waveform at output 1. The output waveform will have good symmetry if R1 = ZR;. The output frequency ls given bythe equation: f=V(+) - Vbe/2R1C1V Whel8 R1 = 2Rg, V35 ii the steady voltage at the inverting input (0.5 V) and V is the difference between the tripping points of the Schmitt trigger.
A suitable circuit is shown, it has the unusual advantage that only the one power supply is required. When the output voltage from the Schmitt trigger circuit is low, the current flowing through Ra is integrated by C; to produce the negative slope of the triangular wave at output 1. When the output 2 voltage from the Schmitt trigger ls high, current flows through R; to produce the rising part of the waveform at output 1. The output waveform will have good symmetry if R1 = ZR;. The output frequency ls given bythe equation: f=V(+) - Vbe/2R1C1V Whel8 R1 = 2Rg, V35 ii the steady voltage at the inverting input (0.5 V) and V is the difference between the tripping points of the Schmitt trigger.
DIY How to Make PCB at Home
It is possible to make PCBs at home with lines as thin as 0.1 mm. And the method is neither difficult nor costly. A hundred pieces of 15cm x 10cm PCBs may cost only Rs 300. The step by step method is:
1. Draw the PCB pattern with black ink (preferably ‘Rotring’) on a white sheet of paper. This step is saved if the pattern is already available (say, from a magazine).
2. Ask a commercial photographer in your town to make a same-size negative of the drawing. A 15cm x 10cm negative may cost around Rs 10.
3. Cut the copper clad laminate in the required size, file its edges till they are smooth, and clean the board with Vim powder, spirit or alcohol. Take it to a dark room (improvised by drawing curtains) and coat it with some photo- resist chemical by pouring some of the chemical over it. (A small night lamp or a red or yellow coloured light may be used in the dark room for working.) Close the photo—resist bottle tightly within 30 seconds so that it is not spoilt by excessive exposure to air. The coated board would dry up within 5 to 10 minutes, after which the negative film may be placed on the board, ensuring that the films enameled side is in contact with the board.
4. Take two plain glass sheets of 6mm thickness with each side of about 30 cms, having holes drilled in all four corners of each sheet. Place the set of negative and copper-clad board in between, with the negative on top. Press the two glass sheets together with the help of four pairs of butterfly nuts and screws fitted in the corner holes, and tighten them carefully (so that you dont crack the glass plates). Cover all these with a thick black colored cloth and take them out in bright sunlight.
5. Remove the cloth for 2-3 minutes if the sunlight is very bright, as at noon, or for 3-4 minutes if its not so bright outside. Again cover them with cloth and bring them back to the dark room. Alternatively, at night, the coated board in glass frame can be exposed to a 200W bulb kept within 7.5 cms for an hour.
6. Pour some photo—resist developer in an enameled or glass bowl tray and immerse the exposed board in it for 60 to 90 seconds. Thereafter, put the board in a water bucket and let the chemicals get washed away thoroughly for a few minutes. The etched PCB pattern will now begin to show on the board.
7. To see the pattern clearly and check it. cover the entire board with a small amount of photo resist dye. Wash the board gently to remove unwanted dye and dry it. Check whether pattern lines are intact or broken. If broken, mend them neatly with resist ink, enamel paint or nail polish. Remove _shorts, if any, carefully with a knife. Place the board on a gas stove or in an oven and bake it for 3 to 5 minutes till A it becomes sufficiently warm but not very hot.
8. Put some ferric chloride in a large glass bowl and pour some hot water on it. After the ferric chloride has dissolved, immerse the board in it. Add a small amount of hydrochloric acid, if you wish to speed up etching. Stirr the solution during etching. Take the PCB out after 20 to 30 minutes and put it in a bucket of water. Wash it thoroughly in water and then wipe out all the chemicals from the board using thinner. Drill the holes at required points and the board is ready for use. Varnish may be used as a protective material for the PCB. Some use a green coloured lacquer to resist solder flow and moisture.
Manufacture The chemicals used being sensitive to light. should be stored in a cool and dry palce away from light. The chemicals and material required for PCB fabrication are avail- able easily in most towns. They are also available in kit form for hobbyists. . As the chemicals for PCBs have odd smell and can be injurious to health, all precautions should be taken in their use. Ventilation, in particular, should be good. Children should not be allowed near the chemicals and smoking should be strictly prohibited in the vicinity. As re-use of the chemicals is not recommended, it is better to make all the pieces you may require of a PCB at one go, instead of remaking them a few days later.
1. Draw the PCB pattern with black ink (preferably ‘Rotring’) on a white sheet of paper. This step is saved if the pattern is already available (say, from a magazine).
2. Ask a commercial photographer in your town to make a same-size negative of the drawing. A 15cm x 10cm negative may cost around Rs 10.
3. Cut the copper clad laminate in the required size, file its edges till they are smooth, and clean the board with Vim powder, spirit or alcohol. Take it to a dark room (improvised by drawing curtains) and coat it with some photo- resist chemical by pouring some of the chemical over it. (A small night lamp or a red or yellow coloured light may be used in the dark room for working.) Close the photo—resist bottle tightly within 30 seconds so that it is not spoilt by excessive exposure to air. The coated board would dry up within 5 to 10 minutes, after which the negative film may be placed on the board, ensuring that the films enameled side is in contact with the board.
4. Take two plain glass sheets of 6mm thickness with each side of about 30 cms, having holes drilled in all four corners of each sheet. Place the set of negative and copper-clad board in between, with the negative on top. Press the two glass sheets together with the help of four pairs of butterfly nuts and screws fitted in the corner holes, and tighten them carefully (so that you dont crack the glass plates). Cover all these with a thick black colored cloth and take them out in bright sunlight.
5. Remove the cloth for 2-3 minutes if the sunlight is very bright, as at noon, or for 3-4 minutes if its not so bright outside. Again cover them with cloth and bring them back to the dark room. Alternatively, at night, the coated board in glass frame can be exposed to a 200W bulb kept within 7.5 cms for an hour.
6. Pour some photo—resist developer in an enameled or glass bowl tray and immerse the exposed board in it for 60 to 90 seconds. Thereafter, put the board in a water bucket and let the chemicals get washed away thoroughly for a few minutes. The etched PCB pattern will now begin to show on the board.
7. To see the pattern clearly and check it. cover the entire board with a small amount of photo resist dye. Wash the board gently to remove unwanted dye and dry it. Check whether pattern lines are intact or broken. If broken, mend them neatly with resist ink, enamel paint or nail polish. Remove _shorts, if any, carefully with a knife. Place the board on a gas stove or in an oven and bake it for 3 to 5 minutes till A it becomes sufficiently warm but not very hot.
8. Put some ferric chloride in a large glass bowl and pour some hot water on it. After the ferric chloride has dissolved, immerse the board in it. Add a small amount of hydrochloric acid, if you wish to speed up etching. Stirr the solution during etching. Take the PCB out after 20 to 30 minutes and put it in a bucket of water. Wash it thoroughly in water and then wipe out all the chemicals from the board using thinner. Drill the holes at required points and the board is ready for use. Varnish may be used as a protective material for the PCB. Some use a green coloured lacquer to resist solder flow and moisture.
Manufacture The chemicals used being sensitive to light. should be stored in a cool and dry palce away from light. The chemicals and material required for PCB fabrication are avail- able easily in most towns. They are also available in kit form for hobbyists. . As the chemicals for PCBs have odd smell and can be injurious to health, all precautions should be taken in their use. Ventilation, in particular, should be good. Children should not be allowed near the chemicals and smoking should be strictly prohibited in the vicinity. As re-use of the chemicals is not recommended, it is better to make all the pieces you may require of a PCB at one go, instead of remaking them a few days later.
Tuesday, September 23, 2014
12V Battery Charger for Sealed Lead Acid
12V Battery Charger for Sealed Lead Acid
There are a number of points we need to cover about the care and use of Sealed Lead Acid batteries.
Firstly, these batteries must be charged, discharged and stored very carefully.
We normally think batteries can be stored for months (if not years) and they will be available for immediate use.
This is not the case with SLA batteries.
If you store a NEW, full charged SLA battery for 6 months or more, you will find it may be fully discharged.
You may also find you cannot charge it!! It may be worthless.
Thats how delicate SLA batteries are.
They must be charged on a regular basis to prevent them discharging to a very low voltage level.
If the terminal voltage of a SLA battery is allowed to go below 8v, aprocess called SULPHATION starts to cover the surface of the plates and prevents the battery being re-charged. The internal resistance of the battery increases and it becomes useless. See products Sealed Lead Acid Battery Charger on Amazon
Parts List of SLA Battery Charger
2 - 1R8 0.5watt resistors
1 - 150R 0.25 watt resistor
1 - 180R
1 - 560R
1 - 1k5
3 - 2k2
1 - 3k3
1 - 4k7
1 - 8k2
1 - 1k mini trim pot
1 - 1n ceramic
2 - 47u 25v electrolytics
1 - 5mm red LED
4 - 1N4148 signal diodes
1 - 10v 0.25watt zener
1 - BC 547 transistor
2 - BC557 transistors
1 - MCR100-6 SCR
1 - 1m red lead
1 - 1m black lead
2 - alligator clips
1 - 2m very fine solder
1 - SLA Battery Charger PCB
Also required:
1 - 12v AC transformer (500mA AC)
1 - power lead
1 - case
Switching Power Supply 13 8V 40A
Switching Power Supply 13 8V 40A
This power supply circuit produces 13.8V regulated to better than 1%, at a continuous load current of up to 40A. It has current limiting, making it appropriate for direct connection to a 12V backup battery. If the current limit potentiometer is turned up, the power supply can deliver up to 60A on an intermittent basis, while maintaining regulation. No minimum load is required. The ripple on the output is about 20mV, and the efficiency is 88%.
More Switching Power Supply
Monday, September 22, 2014
Audio Clipping Indicator circuit and explanation
Detects clipping in preamp stages, mixers, amplifiers etc., Single LED display – 9V Battery supply unit
This circuit was intended to be used as a separate, portable unit, to signal by means of a LED when the output wave form of a particular audio stage is “clipping” i.e. is reaching the onset of its maximum permitted peak-to-peak voltage value before an overload is occurring. This will help the operator in preventing severe, audible distortion to be generated through the audio equipment chain. This unit is particularly useful in signaling overload of the input stages in mixers, PA or musical instruments amplification chains, but is also suited to poweramplifiers. A careful setting of Trimmer R5 will allow triggering of the LED with a wide range of peak-to-peak input voltages, in order to suit different requirements. Unfortunately, an oscilloscope and a sine wave frequency generator are required to accurately setup this circuit. Obviously, the unit can be embedded into an existing mixer, preamp or power amplifier, and powered by the internal supply rails in the 9 – 30V range. The power supply can also be obtained from higher voltage rails provided suitable R/C cells are inserted. SW1 and B1 must obviously be omitted.
Circuit diagram:
Audio Clipping Indicator Circuit Diagram
Parts:
R1_______________1M 1/4W Resistor (See Notes)
R2,R3,R8_______100K 1/4W Resistors
R4,R6___________10K 1/4W Resistors
R5_______________5K 1/2W Trimmer Cermet or Carbon
R7_______________2K2 1/4W Resistor
R9______________22K 1/4W Resistor
R10______________1K 1/4W Resistor (See Notes)
C1,C4__________220nF 63V Polyester Capacitors
C2_______________4p7 63V Ceramic Capacitor (See Notes)
C3_____________220µF 25V Electrolytic Capacitor
C5______________10µF 25V Electrolytic Capacitor (See Notes)
D1,D2________1N4148 75V 150mA Diodes
D3______________LED (Any dimension, shape and color)
Q1____________BC547 45V 100mA NPN Transistor
IC1___________TL062 Dual Low current BIFET Op-Amp (or TL072, TL082)
SW1____________SPST Toggle or Slide Switch (See Text)
B1_______________9V PP3 Battery (See Text)
Circuit operation:
The heart of the circuit is a window comparator formed by two op-amps packaged into IC1. This technique allows to detect precisely and symmetrically either the positive or negative peak value reached by the monitored signal. The op-amps outputs are mixed by D1 and D2, smoothed by C4, R7 and R8, and feed the LED driver Q1 with a positive pulse. C5 adds a small output delay in order to allow detection of very short peaks.
Notes:
- With the values shown, the circuit can be easily set up to detect sine wave clipping from less than 1V to 30V peak-to-peak (i.e. 15W into 8 Ohms). If you need to detect higher output peak-to-peakvoltages, R1 value must be raised. On the contrary, if the circuit will be used to detect only very low peak-to-peak voltages, it is convenient to lower R1 value to, say, 220K omitting C2. In this way, the adjustment of R5 will be made easier.
- Using a TL062 chip at 9V supply, stand-by current drawing is about 1.5mA and less than 10mA when the LED illuminates. With TL072 or TL082 chips, current drawing is about 4.5mA and 13mA respectively.
- When using power supplies higher than 12V, the value of R10 must be raised accordingly.
- When using power supplies higher than 25V, the working voltage value of C5 must be raised to 35 or 50V.
Sunday, September 21, 2014
Mini Guitar Bass Amplifier
Output power: 6W into 4 Ohm load, FET input stage – Passive Tone Control
Tiny, portable Guitar Amplifiers are useful for practice on the go and in bedroom/living room environment. Usually, they can be battery powered and feature a headphone output. This project is formed by an FET input circuitry, featuring a High/Low sensitivity switch, followed by a passive Tone Control circuit suitable to Guitar or Bass. After the Volume control, a 6W IC power amplifier follows, powered by a 12-14V dc external supply Adaptor or from batteries, and driving a 4 Ohm 10 or 13cm (4″/5″) diameter car loudspeaker. Private listening by means of headphones is also possible.
Circuit diagram:
Mini Guitar-Bass Amplifier Circuit Diagram
Parts:
P1______________1M Linear Potentiometer
P2____________100K Log Potentiometer
R1_____________68K 1/4W Resistor
R2____________470K 1/4W Resistor
R3______________2K7 1/4W Resistor
R4______________8K2 1/4W Resistor
R5____________680R 1/4W Resistor
R6____________220K 1/4W Resistor
R7_____________39R 1/4W Resistor
R8______________2R2 1/4W Resistor
R9____________220R 1/4W Resistor
R10_____________1R 1/4W Resistor
R11___________100R 1/2W Resistor
R12_____________1K5 1/4W Resistor
C1____________100pF 63V Polystyrene or Ceramic Capacitor
C2,C5,C9,C14__100nF 63V Polyester Capacitors
C3____________100µF 25V Electrolytic Capacitor
C4_____________47µF 25V Electrolytic Capacitor
C6______________4n7 63V Polyester Capacitor
C7____________470pF 63V Polystyrene or Ceramic Capacitor
C8______________2µ2 25V Electrolytic Capacitor
C10___________470µF 25V Electrolytic Capacitor
C11____________22nF 63V Polyester Capacitor
C12__________2200µF 25V Electrolytic Capacitor
C13__________1000µF 25V Electrolytic Capacitor
D1______________3mm red LED
Q1____________BF245 or 2N3819 General-purpose N-Channel FET
IC1_________TDA2003 10W Car Radio Audio Amplifier IC
SW1,SW2________SPST toggle or slide Switches
J1____________6.3mm Mono Jack socket
J2____________6.3mm Stereo Jack socket (switched)
J3_____________Mini DC Power Socket
SPKR__________4 Ohm Car Loudspeaker 100 or 130mm diameter
| Elektor 303 Circuit |
| Practical Arduino |
| Elektor05-2010 |
| Elektor05-2010 |
| Elektor05-2010 |
| Nuts Volts 06-2010 |
| Nuts Volts 06-2010 |
source: http://electronicsprojects.mediadir.in/mini-guitarbass-amplifier/
Notes:
- Connect the output Plug of a 12 – 14V dc 500mA Power Supply Adaptor to J3
- Please note that if the voltage supply will exceed 18V dc the IC will shut down automatically
Technical data:
Output power (1KHz sinewave):
6W RMS into 4 Ohm at 14.4V supply
Sensitivity:
50mV RMS input for full output
Frequency response:
25Hz to 20kHz -3dB with the cursor of P1 in center position
Total harmonic distortion:
0.05 – 4.5W RMS: 0.15% 6W RMS: 10%
Tone Control Frequency Response:
1000W Power Amplifier
Circuit Description 1000W Power Amplifier:
Power amplifier has up to 1000 Watt power, this circuit made one channel only so if you want to create a stereo in it must be made one again, actually this is more suitable power amplifier in use for Sound System or outdoor, so if only in use for the house I think is less suitable.
Maybe youve seen or even have an active speaker and there is written 1500 watts PMPO (Peak Music Power Output), make no mistake this is different from Power Amplifier Active Speaker, I often dismantle such Active Speaker in it only a power with power no more than 150 watts by using the transformer 2-3 Ampere. PMPO is not a real power which is issued by the Power Amplifier, but counting all the speakers that there is, for example: if there are 5 pieces of speakers on each channel and each speaker has a power of 10 W then it is 100 W PMPO.
Circuit Diagram 1000W Power Amplifier:
Circuit Diagram 1000W Power Amplifier:
 |
| 1000W Power Amplifier |
Partlist 1000W Power Amplifier:
While this 1000 Watt Power Amplifier minimal use transformer 20 Ampere. And the output of PowerAmplifier DC voltage contains approximately 63 volts, with currents and voltages of this magnitude, this 1000 Watt Power Amplifier will not hesitate hesitate to destroy your woofer speakers to connect. To overcome that then before the speaker on connects to 1000 Watt Power Amplifier must be in pairsSpeaker Protector.
Actually if you want to create a Power Amplifier with great power does not have to make a PowerAmplifier with great power. Example: you want to create a Power Amplifier with 10 000 Watt power. You do not have to assemble a Power Amplifier with power of 10,000 watts, but you assemble thepower Power Amplifier Small but many, such as you assemble the Power Amplifier with 1000 Watts of power for as many as 10 pieces, it will produce 10 000 Watt Power Amplifier helpless.
Circuit uses power transistors pair of 5 x 5 x 2SA1216 and 2SC2922 and 2SC1583 use a differentialamplifier that actually contains 2 pieces of transistors that are in containers together. Why use such built-in amplifier differental tujuanya so identical / similar, could have uses 2 separate transistors but can result in amplifier so it is not symmetrical.
Tips combining speaker.
To get the speakers with great power combining techniques can be used in parallel series, combining each group of speakers should sepaker they will have the same impedance, the same type (Woofer, Mid Range or tweeter) and the same power. Number of merging these speakers should consists of 4 , 9, 16 ff, see picture
Example: The number of speakers have 4 pieces each of its 200 Watt power generated will be aspeaker at = 200 x 4 = 800 Watt. If there are 9 speakers 200 W then the result = 9 x 200 W = 1800Watt.
Fuse Box Toyota 1985 Celica Engine Compartment Diagram
Fuse Box Toyota 1985 Celica Engine Compartment Diagram - Here are new post for Fuse Box Toyota 1985 Celica Engine Compartment Diagram.
Fuse Panel Layout Diagram Parts: headlight control relay, fan relay, radio, RTR, engine main relay, Head lamp, hazzard, horn, charge relay, headlamp, EFI main relay.
Read More..
Fuse Box Toyota 1985 Celica Engine Compartment Diagram
Fuse Panel Layout Diagram Parts: headlight control relay, fan relay, radio, RTR, engine main relay, Head lamp, hazzard, horn, charge relay, headlamp, EFI main relay.
Saturday, September 20, 2014
Circuit diagram capacitor charge control
The scheme is designed to protect against inrush current when the battery uncharged capacitor on-board network. Who has not tried to include uncharged faradnik network without limiting resistor - better not ... At a minimum, get burnt contacts.
When you turn the discharged capacity in network capacity C1 is discharged, T1 (n-MOSFET switch with low channel resistance) is closed.Capacitance C2 (the same faradnik) is charged through a low-resistance R5. T2 opens almost instantly, the shunt to ground C1 and T1 gate.When the potential negative terminal C2 falls below 1V (charge to Uakb - 1B), T2 closes smoothly C1 is charged to about 9/10 Uakb opening T1. The time constant R2C1 is large enough so that the current surge T1 (pre-charge C2 +1 V to Uakb) does not exceed the rating for T1.
In the future, the negative terminal of C2 constantly shorted to ground through T1, regardless of the direction CURRENT T1 (both literally - from drain to source, and in the opposite direction). Nothing wrong with "rollover" OPEN TIR transistor not. When choosing a good enough conductive transistor entire reverse current flow through the channel, and a built-wheeling diode will not open because the voltage drop across the channel at times less than required for the opening of 0.5-0.8 V. By the way, there is a whole class of TIR devices (eg FETKY ), designed specifically to work in the opposite direction (synchronous rectifiers), they have built a diode is shunted by an additional force Schottky diode.
Calculation: for transistor IRF1010 (Rds = 0.012 ohms) voltage drop of 0.5 ohms will only be achieved with the current channel 40A (P = 20W).For four of these transistors in parallel and the same discharge current of 40A - on each transistor will dissipate 0,012 * (40/4) ^ 2 = 1.2 W, ieradiators they are not required (the more that will dissipate 1.2W only when differential current consumption but not consistently).
Dense installation (you have plenty of space for extra radiator?) - Advisable parallels small (body TO251, DIP4) transistors, generally do not provide radiators, based on the ratio of current (power) consumption of the amplifier - Rds - limit power dissipation. Since Pds max is typically 1W (800 mW for DIP4), the number of n transistors (c Rds each) for the amplifier with an output power Pout must be at least n> 1/6 * Pout * sqrt (Rds) at 12V supply (dimension in the formula I omitted). In fact, given the short duration current pulses, n can be easily reduced by half compared with a given formula.
Resistor R5 is selected from the charge compromise heat output and charging time. When these 22 ohms - charge time of about 1 minute at power dissipation 7 watts. R5 can instead include 12V bulb, say, indicator. Resistors R1, R3 - reinsurance (discharged capacity when disconnected from the network).
Connect to indicate activation of additional inverter (reducing R2). Attention! The scheme is efficient at using npn transistors T2, T3 with h21e> 200 (KT3102). Depending on the brightness of the LED, R1, select the range of 200 ohms - 1k.
But the view of the circuit in which the key shutter control signal REMOTE (And transistor). The non-connected or off REMOTE key transistor guaranteed closed. D3-D4 LEDs indicate charging C1, D5-D6 - the open state of the key.
Accurate indication of the threshold voltage is provided easiest IP TL431 (KR142EN19) in a typical mode voltage comparator (with the corresponding subgroup in the input circuit and current-limiting circuit cathode R).
Loss schemes largely depend on the installation. Ensure that the minimum resistance (and corresponding current thickness of the wires) in the power circuit (terminal + / C2 / T1 /-terminal). In amateur practice, I think, make outgoing terminals impractical - it is better to unsolder the short wires AWG8, which binds to the terminal block diagram of the amplifier.
Original article source cxem.net
Fuse Box BMW 1983 86 635CSi Diagram
Fuse Box BMW 1983-86 635CSi Diagram - Here are new post for Fuse Box BMW 1983-86 635CSi Diagram.
Fuse Panel Layout Diagram Parts: high beam relay, low beam relay, auxiliary fan, turn signal, windshield wiper, intensive cleaner, brake light, cruise control, horn, engine electrical equipment, back up light, instrument cluster, main and auxiliary relay, duel pump, radio, cjeck control, heater blower, back up light, power mirror, mirror heating, air conditioner, fasten seat belt, power seat memory, auxiliary fan, power sliding roof, heated seat, rear window defogger, interior light, radio glove box, radio, hazard waarning light, power seat, central locking system, power seat, lighter, power antenna, fog light.
Read More..
Fuse Box BMW 1983-86 635CSi Diagram
Fuse Panel Layout Diagram Parts: high beam relay, low beam relay, auxiliary fan, turn signal, windshield wiper, intensive cleaner, brake light, cruise control, horn, engine electrical equipment, back up light, instrument cluster, main and auxiliary relay, duel pump, radio, cjeck control, heater blower, back up light, power mirror, mirror heating, air conditioner, fasten seat belt, power seat memory, auxiliary fan, power sliding roof, heated seat, rear window defogger, interior light, radio glove box, radio, hazard waarning light, power seat, central locking system, power seat, lighter, power antenna, fog light.
Friday, September 19, 2014
Gold Detector Schematic
Here the very simple and easy build gold detector schema. The schema capable to sense gold or metal or coins from a distance of about 20cm, depending on the size of the object to detect.
The schema oscillates at about 140kHz and a harmonic of this frequency is detected by an AM radio. You can simply tune the radio receiver until a squeal is detected.
When the search coil is placed near a metal object, the frequency of the schema will change and this will be heard from the speaker of AM radio.
Below image is the construction of the schema, you will see that the radio is placed on the hand stick of the complete detector.
Thursday, September 18, 2014
Explanation Fuse Box Chevrolet Tracker Instrument Panel 2001 Diagram
Fuse Box Chevrolet Tracker Instrument Panel 2001 Diagram - This show you about Fuse Box Chevrolet Tracker Instrument Panel 2001 Diagram.
Fuse Panel Layout Diagram Parts: power window, dome light, license plate light, marker light, instrument panel illumination, hazard light, sensor heater, cruise control, ignition coil, meter, G sensor, cigar lighter, radio, power mirror, door lock, brake light, horn, stop lamp, rear window defogger, daytime running light, turn signal, back up light, windshield wiper, washer, rear window.
Read More..
Fuse Box Chevrolet Tracker Instrument Panel 2001 Diagram
Fuse Panel Layout Diagram Parts: power window, dome light, license plate light, marker light, instrument panel illumination, hazard light, sensor heater, cruise control, ignition coil, meter, G sensor, cigar lighter, radio, power mirror, door lock, brake light, horn, stop lamp, rear window defogger, daytime running light, turn signal, back up light, windshield wiper, washer, rear window.
Wednesday, September 17, 2014
IC LM35 Temperature Sensor Characteristics
LM 35 temperature sensor IC is a IC chip production Natioanal Semiconductor which serves to determine the temperature of an object or space in the form of electric scale, or can also be defined as an electronic component that is used to change the temperature changes are accepted in the electrical wholesale changes. LM35 temperature sensor IC temperature change can change a change in voltage at the output. LM35 temperature sensor IC requires +5 volts DC source voltage and DC current consumption of 60 mA in operation. Physical form LM 35 temperature sensor is an IC chip with packaging that varies, in general packaging LM35 temperature sensor is packaged TO-92 as shown in the figure below.
IC LM35 Temperature Sensor Characteristics
From the picture above it can be seen that the temperature sensor IC LM35 basically have 3 pin that serves as a source of supply voltage of +5 volts DC, as a result of sensing the output pin in the form of a change in the DC voltage and Vout pin to Ground.
IC LM35 temperature sensor characteristics are:
- Temperature sensitivity, with linear scaling factor between voltage and temperature 10 mVolt / º C, so it can be calibrated directly in centigrade.
- Have the accuracy or the accuracy of the calibration is 0.5 º C at 25 º C.
- Has a maximum operating temperature range between -55 º C to +150 º C. Working at a voltage of 4 to 30 volts.
- Has current low at less than 60 mA.
- Have a low self-heating (low-heating) of less than 0.1 º C in still air.
- Has a low output impedance is 0.1 W for 1 mA load.
- have Nonlinearities only about ± ¼ º C.
Tuesday, September 16, 2014
Fuse Box Toyota 1998 Lexuz GS400 Diagram
Fuse Box Toyota 1998 Lexuz GS400 Diagram - Here are new post for Fuse Box Toyota 1998 Lexuz GS400 Diagram.
Fuse Panel Layout Diagram Parts: fog fuse, tail light, gauge, fuel OPN, door fuse, stop lamp fuse, panel fuse, heater fuse, power seat fuse, ignition coil, washer fuse, cigar lighter, ECU ignition, starter fuse.
Read More..
Fuse Box Toyota 1998 Lexuz GS400 Diagram
Fuse Panel Layout Diagram Parts: fog fuse, tail light, gauge, fuel OPN, door fuse, stop lamp fuse, panel fuse, heater fuse, power seat fuse, ignition coil, washer fuse, cigar lighter, ECU ignition, starter fuse.
Monday, September 15, 2014
P CAD Software
Powerful computer-aided design of printed circuit boards and electronic computing devices.
The program is able to complete the entire cycle of PCB design and deployment of interactive autotrace guides, troubleshooting at any stage of the project, preparation of documentation, check the integrity of all signals, crosstalk analysis.Easy referral system and user interface reduce "barrier to entry" for beginners.
The program is able to complete the entire cycle of PCB design and deployment of interactive autotrace guides, troubleshooting at any stage of the project, preparation of documentation, check the integrity of all signals, crosstalk analysis.Easy referral system and user interface reduce "barrier to entry" for beginners.
P-CAD consists of two independent modules - Schematic (Editor electrical circuits) and PCB (printed circuit board editor).Projects schemes can contain up to 999 sheets and draft boards - up to 999 layers of size 60x60 inches.There are opportunities for interactive routing of differential pairs to minimize electromagnetic interference multimarshrutnaya tracing the specified parameters, orthogonal dragging conductors.Besides the basic routines P-CAD has support: Library Executive (library manager), Symbol Editor (Editor symbols of the elements), Pattern Editor (Editor seats, housings elements) and some others.P-CAD libraries store more than 27,000 items, certified according to ISO 9001.Fully supported formats Gerber and ODB + +.
Among the recent improvements to P-CAD - adding tracer Situs powerful design environment of Altium Designer , CAMtastic package for the preparation of printed circuit board to the production and service analog and digital simulation and nVisage Xspice.
In 1996 the company ACCEL Technologies presented to the public the first version of P-CAD called ACCEL EDA. The product has gained popularity among designers of digital devices. January 17, 2000 ACCEL Technologies was acquired leading developer of CAD Protel International. In March 2000, ACCEL EDA changed its name to P-CAD. Today it is the most famous in Russia design environment. On the Internet there are lots of information about this program.
Computer-aided design using English interface. Proven or official russifiers not. Using True Type fonts allows inscriptions in Russian.
In summer 2006, the owner of the program Australian company Altium formally announced that it would stop the development of P-CAD.Developers were invited to go to Altium Designer - a powerful product company. In spring 2008, the company announced the termination of proprietary (English-language) support. After June 30, 2008, legally purchased P-CAD can not.
The latest official version became a P-CAD 2006 SP2 released in 2006.
P-CAD 2006 is fully operational only in the operating systems Windows XP, Windows 2000, Windows 98, Windows 95, Windows NT.
P-CAD 2006 is fully operational only in the operating systems Windows XP, Windows 2000, Windows 98, Windows 95, Windows NT.
The official website for P-CAD: http://www.altium.com
Sunday, September 14, 2014
2 x 32W DUAL BRIDGE CAR RADIO AMPLIFIER TDA7393
Features:
Circuit Diagram:
- HIGH OUTPUT POWER CAPABILITY:
- 2 x 35W max./4Ω
- 2 x 32W EIAJ/4Ω
- 2 x 22W typ./4Ω @ 14.4V, 1KHz, 10%
- 2 x 19W typ./4Ω @ 13.2V, 1KHz, 10%
- 2 x 28W typ./2Ω @ 14.4V, 1KHz, 10%
- 2 x 25W typ./2Ω @ 13.2V, 1KHz, 10%
- LOW DISTORTION
- LOW OUTPUT NOISE
- ST-BY FUNCTION
- MUTE FUNCTION
- AUTO-MUTE AT MIN. SUPPLY VOLTAGE
- DETECTION
- LOW EXTERNAL COMPONENT COUNT
- – INTERNALLY FIXED GAIN (32dB)
- – NO EXTERNAL COMPENSATION
- – NO BOOTSTRAP CAPACITORS
- ADDITIONAL MONO INPUT
- OUTPUT AC/DC SHORT CIRCUIT TO GND
- AND TO VS
- VERY INDUCTIVE LOADS
- OVERRATING CHIP TEMPERATURE WITH
- SOFT THERMAL LIMITER
Circuit Diagram:
 |
| 2 x 32W DUAL BRIDGE CAR RADIO AMPLIFIER |
Modifying your Auto Sound System
If you are one of the many people around the world who happens to be into cars and the new pastime called modding Im sure you have considered the implications of modding your auto sound system. For many the idea of modifying an automobile is very exciting. Its a way to take the standard canvas purchased from the dealer and turn it into a work of art that you drive to work and play each and every day. The same theory holds for your sound system as well. You can take the basic pieces and parts and turn them into something so much more than they were to begin with.
If that isnt enough you can purchase all kinds of LED lights and other nifty gadgets that glow and go along with your car while dancing to the beat. If you want to make a splash driving down any boulevard, this is definitely one way to not only be seen but also leave a lasting impression. Your creative genius with your auto sound system will cause quite a stir and give plenty of people much to discuss the next morning and plenty of people a great deal of inspiration to try to mimic or at the very least incorporate into their units somehow.
There are all kinds of sound systems for automobiles. Many of these systems are sold as part of a package and readily available to multiple consumers. You have the option as a creative modding genius, to take the plane Jane package and turn it into something so much better than it is or to even go off on a tangent and invent a total package of your own by mixing and matching pieces and parts from several different packages or pieces of packages.
It doesnt matter where your creativity ends and begins there is never a challenge too great for a true modder at heart. From cars, trucks, boats, and computers to car stereos there is no task too demanding or too complicated for a true modding mind to tackle and transform. Perhaps its the blinking lights or all the wonderful possibilities that abound but auto sound system mods are among my favorite to see in action. Its amazing the things that can be thought up by a wicked imagination and accomplished with a little time and a lot of effort.
Seriously though, if you are going to go to all the trouble of dressing up your vehicle shouldnt you also take the time to dress up your auto sound system? There are all kinds of gadgets and gizmos you can buy that will work with the music your speakers are pumping in order to create a fabulous overall affect of music and light that is sure to get some great reactions from those you cruise on by. These are perfect accessories for summer time beach driving if you know what I mean. Growing up on the coast, I found a great section of people who were constantly modifying their cars and sound systems. I think it is incredibly amazing what can be done with metal, glass, color, light, and sound and really enjoy seeing all of the amazing creations that are made.
Even if you havent really given much thought to modifying your auto sound system before, I hope that you will consider it now if you are a serious modder. I honestly believe you might amaze yourself at some of the fabulous tricks of sound and light that you can come up with when properly challenged and inspired.
Take the time to check out the interesting things that have been done, and then formulate a hypothesis on what can be done. It is truly amazing the wonderful things that have been created as the result of a glove being thrown so to speak. Jump in and create a fabulously modified sound system that will be the absolute envy of everyone you pass along the way.
Saturday, September 13, 2014
Yes No Indicator Has Zero Standby Current
This schema produces a random "Yes" or "No" with a single button press - indicated by the illumination of a red or green LED. The schema has two advantages over similar diagram. First, it uses just a single momentary contact pushbutton, so no on-off switch is required. When the pushbutton is pressed, an oscillator comprising the 10nF capacitor and 22kΩ resistor at pins 1 & 2 is almost immediately stopped by FET Q1, which pulls the oscillators timing capacitor to the positive rail. However, the 220nF capacitor and 470kΩ resistor in the gate schema of Q1 introduce a tenth of a seconds delay, so that about 250 oscillations take place before the clock is stopped.
Due to variations in charge on the diagram capacitors, as well as voltage and temperature variations, and the unpredictability of when the pushbutton will be pressed, randomness is assured. The schema has a high degree of randomness because it takes advantage of a near-perfect complementary square waveform at pins 10 and 11 of the 4047 IC. The oscillator frequency (available at pin 13) is passed through an internal divide-by-2 schema in the 4047. This appears at pin 10 (Q), and is inverted at pin 11 (Q-bar), thus assuring a near perfect 50:50 duty cycle for the two LEDs.
Yes-No Indicator Circuit Diagram
Note:
However, that the "impartiality" of the schema is partly contingent on the value of the 10nF capacitor and on a reasonably equal current flow through both LEDs. Over five trials, the Yes-No Indicator scored 142 Yes, 158 No, with Yes falling behind No in the fourth trial. Because the schema only works while switch S1 is pressed, standby current is zero, therefore a miniature 12V battery may be used to power it. In this case the schema could be used thousands of times before the battery would run flat. The schema has a further potential use. If the LEDs are omitted and a piezo (capacitive) sounder is wired directly to pins 10 and 11, it will produce a loud beep when equipment is turned on, and will continue to draw less than 0.5mA until it is switched off. The frequency of the beep may be changed by altering the value of the 10nF capacitor and its duration by altering the value of the 220nF capacitor.
However, that the "impartiality" of the schema is partly contingent on the value of the 10nF capacitor and on a reasonably equal current flow through both LEDs. Over five trials, the Yes-No Indicator scored 142 Yes, 158 No, with Yes falling behind No in the fourth trial. Because the schema only works while switch S1 is pressed, standby current is zero, therefore a miniature 12V battery may be used to power it. In this case the schema could be used thousands of times before the battery would run flat. The schema has a further potential use. If the LEDs are omitted and a piezo (capacitive) sounder is wired directly to pins 10 and 11, it will produce a loud beep when equipment is turned on, and will continue to draw less than 0.5mA until it is switched off. The frequency of the beep may be changed by altering the value of the 10nF capacitor and its duration by altering the value of the 220nF capacitor.
Author: Thomas Scarborough - Copyright: Silicon Chip Electronics
1000W Power Amplifier
Sound Activated Lights
This diy sound activated lights schema turns a lamp ON for a short duration when the dog barks (or a relatively strong sound) giving an impression that the occupants have been alerted. The condenser microphone fitted in a place to monitor sound and generates AC signals, which pass through DC blocking capacitor C1 to the base of transistor BC549 (T1). Transistor T1 along with transistor T2 amplifies the sound signals and provides current pulses from the collector of T2. When sound is produced in front of the condenser mic, triac1 (BT136) fires, activates lights and the bulb (B1) glows for about two minutes.
Sound Activated Lights Circuit Diagram
Sound Activated Lights Circuit Diagram
Assemble the sound activated lights schema on a general purpose PCB (schema board) and enclose in a plastic cabinet. Power to the sound activated switch schema can be derived from a 12V, 500mA step-down transformer with rectifier and smoothing capacitor. Solder the triac ensuring sufficient spacing between the pins to avoid short schema. Fix the unit in the dog’s cage or close to the sound monitoring spot, with the lamp inside or outside as desired. Connect the microphone to the sount activated lights schema using a short length of shielded wire. Enclose the microphone in a tube to increase its sensitivity.
Caution. Since the sound activated lights uses 230V AC, many of its points are at AC mains voltage. It could give you lethal shock if you are not careful. So if you don’t know much about working with line voltages, do not attempt to construct this schema. We will not be responsible for any kind of resulting loss or damage.
Friday, September 12, 2014
Subwoofer Amplifier Circuit 60W
Using the STK4038X audio amplifier IC, can be designed a very simple high power and efficiency audio power amplifier . This circuit is manufactured by Sanyo Corporation and will provide a output power of 60 watts on a 8 ohms load or 4 ohms load with 0.008% distortion . The output power that is provided by this audio IC , can be more higher , but with more distortion.If you will use a 8 ohms load you must power this audio amplifier project from a dual +/- 40 volts DC power supply and if you’ll use a 4 ohms load you must power this audio project form a dual +/- 33.5 volts DC power source. To prevent over heating the STK4038X audio power IC must be heatsinked on a good heatsink . Also you must use a very well filtered power supply ( a 10000uF capacitor will be fine for this audio project) .
Simple Touch Switch
With touch switch, you can turn on and turn on a electronic device. Touch switch dont need mechanical part, so they will not worn out due to mechanical contact. Touch switches can be used in places where regular switches would not last, such as wet or very dusty areas.
Here the schematic diagram:
Component part list:
Notes:
1. The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.
2. When activated, the output of the schema goes high for about one second. This pulse can be used to drive a relay, transistor, other logic, etc.
3. You can vary the length of the output pulse by using a smaller or larger capacitor for C1.
Read More..
Here the schematic diagram:
Component part list:
Part Total Qty. Description
C1 1 10uF 16V Electrolytic Capacitor
R1, R2 2 100K 1/4 Watt Resistor
R3 1 10 Meg 1/4 Watt Resistor
U1 1 4011 CMOS NAND Gate IC
MISC 1 Board, Wire, Socket For U1
Notes:
1. The contacts an be made with just two loops of wire close together, or two squares etched close together on a PC board.
2. When activated, the output of the schema goes high for about one second. This pulse can be used to drive a relay, transistor, other logic, etc.
3. You can vary the length of the output pulse by using a smaller or larger capacitor for C1.
Latest Tab Google captures your 3D environment It cost U S 1 024
Google introduces its tablet the Tango Project, a project that handles allow you to create 3D maps of the environment of a mobile device.
The Project Tango Tablet, as Google calls it for now, is mainly designed for developers interested in exploring the future of 3D technology on a mobile device can do so and to develop new features that may allow it to another level bringing this technology, as mentioned Google.
The 7-inch tablet that goes on sale later this year is priced at U.S. $ 1.024, making it not the cheapest in the market.
However, Googles tablet was created with help from Nvidia to allow create internal maps of buildings in 3D, thanks to various cameras and sensors that are in the device. The tablet has a Nvidia Tegra K1 processor, 4GB of RAM, 128GB of storage, Wi-Fi and 4G LTE.
Although the Tango Project or Project Tango would be in its initial phase, the new tablet could help take an important step for this kind of technology can reach consumers in the future.
LCD Module in 4 bit Mode
LCD Module in 4-bit Mode Circuit diagram. In many projects use is made of alphanumeric LCDs that are driven internally by Hitachi’s industry-standard HD44780 controller. These displays can be driven either in 4-bit or 8-bit mode. In the first case only the high nibble (D4 to D7) of the display’s data bus is used. The four unused connections still deserve some closer attention. The data lines can be used as either inputs or outputs for the display. It is well known that an unloaded output is fine, but that a floating high-impedance input can cause problems. So what should you do with the four unused data lines when the display is used in 4-bit mode? This question arose when a schema was submitted to us where D0-D3 where tied directly to GND (the same applies if it was to +5 V) to stop the problem of floating inputs.
The LCD module was driven directly by a microcontroller, which was on a development board for testing various programs and I/O functions. There was a switch present for turning off the enable of the display when it wasn’t being used, but this could be forgotten during some experiments. When the R/Wline of the display is permanently tied to GND (data only goes from the microcontroller to the display) then the remaining lines can safely be connected to the supply (+ve or GND). In this application however, the R/Wline was also controlled by the microcontroller. When the display is initialised correctly then nothing much should go wrong. The data sheet for the HD44780 is not very clear as to what happens with the low nibble during initialisation.
LCD Module in 4-bit Mode Circuit diagram :
LCD Module in 4-bit Mode Circuit Diagram
After the power-on reset the display will always be in 8-bit mode. A simple experiment (see the accompanying schema) reveals that it is safer to use pull-down resistors to GND for the four low data lines. The data lines of the display are configured as outputs in this schema (R/Wis high) and the ‘enable’ is toggled (which can still happen, even though it is not the intention to communicate with the display). Note that in practice the RS line will also be driven by an I/O pin, and in our schema the R/W line as well. All data lines become high and it’s not certain if (and if so, for how long) the display can survive with four shorted data lines. The moral of the story is: in 4-bit mode you should always tie D0-D3 via resistors to ground or positive.
K574UD1 generator audio range
In the development and research of electronic equipment in the laboratory one of the most important components of the measurement equipment is a universal source of test signals. Function generator, working in a range of sound frequencies, was developed based on a microcontroller. It is based on generator circuit described in [Radiohobby, 2000, № 5, p. 79]. The analysis of this scheme it was revealed a significant disadvantage. Because the counter is formed by two functional elements, the logic levels on the address pins are not installed simultaneously, which leads to the appearance of high-frequency emissions of the generator output. Developed device devoid of these deficiencies. Generated output waveform (saw, triangle, sine, square wave) programmed in flash-memory. The generator used firmware contained in [Radiohobby, 2000, № 5, p. 79]. Schematic diagram of the function generator is shown in Fig. 1.The main technical parameters:
Range of generated frequencies, Hz
0 ... 30000
Flatness dB
<0.3
The amplitude of the output voltage, V
4
Number of steps output
128 128
MS 4046 on a chip (DD1) assembled an oscillator, which control the frequency tuning in the range 0 ... 4 MHz. Variable resistor R1 is a multiple of the frequency control. On-chip 556IE10 (DD2) assembled address counter which outputs signals are formed ("typed address") applied to the address inputs of the PROM Winbond W27C512 (DD4). In this flash-memory chip programmed forms of output signals. With PROM outputs signals are sent to the DAC DAC0800 (DA4), from which output signal is fed to a high-speed operational amplifier K574UD1 (DA5). SB1 button is used to select the output waveform. The components of the chip 155LAZ (DD3.2, DD3.3) Assemble debounce buttons SB1. With the terminals 5 and 9, which also receives signals from the outputs of the PROM, the signal goes to the chip decoder SN74LS156N (DD7). With its removable data outputs the selected signal that displays one of the LEDs. For indicating the selected output waveform is assembled unit to the D-flip-flop circuits 155TM2 (DD6), the input of which receives impulses originating switching button. The unit is powered from the unregulated voltage source + 12, which enters the integral timer DA1 and positive voltage stabilizer DA2. Timer DA1 implemented multivibrator, the output of which removed rectangular pulses. They are rectified and is input to the negative voltage regulator DA3. The voltage from its output is used to power a generator. When setting up the device you first need to set the frequency of the selection of C1-order 4 MHz at pin 4 chips DD1, then the resistor R11 to generate sine wave mode, controlling the output of an oscilloscope, to establish the symmetry of the signal relative to the total wire. The maximum output frequency of the oscillator is determined primarily by the speed of EEPROM, which for the chip Winbond W27C512 is approximately 4 MHz, so the maximum output frequency: 4 MGts/128 stages = 30 kHz. Measured harmonic distortion of the sinusoidal signal constitute 0.0076% at 1 kHz. This generator is designed to work with a digital oscilloscope, which displays the frequency of the input signal, so additional indication output signal frequency is not provided. The devices made on microcontrollers, promising enough. For example, the proposed generator can be increased through the use of frequency oscillator with greater frequency. Also by increasing the bit of flash-memory can increase the frequency of sampling. The generator can be connected to a PC with the ability to programmatically change the shape of the output signal due to changes in firmware flash-memory. Resistor R1 - SP5-44-1 or other reusable, R9, R11 - SPZZa or other small.
Original article source cxem.net
Original article source cxem.net
Thursday, September 11, 2014
Low Power Wireless Audio Power Amplifier
Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and Loud Speaker. In place of a pair of wires, it uses invisible infra-red light to transmit audio signals from TV to Loud speakers, Without using any lens a range of up to 6 meters is possible. Range can be extended by using lenses and reflectors with IR sensors comprising transmitters and receivers.
IR transmitter uses two-stage transistor amplifier to drive two series-connected IR LEDs. An audio output transformer (T1) is used (in reverse) to couple audio output from TV to the IR transmitter. Transistors Q1 and Q2 amplify the audio signals received from TV through the audio transformer. Low impedance output windings (lower gauge or thicker wires) are used for connection to TV side while high-impedance windings are connected to IR transmitter. This IR transmitter can be powered from a 9V mains adapter or a 9V battery. Red LED (D1) in transmitter circuit functions as a Zener diode (0.65V) as well as supply-on indicator.
Transmitter diagram:
 |
| Wireless Audio Power Amplifier Transmitter Circuit Diagram |
Receivers operation:
IR receiver uses popular op-amp IC µA741 and audio-frequency amplifier IC LM386 along with phototransistor L14F1 (Q3) and some discrete components. The sound generated by TV set is transmitted through IR LEDs, received by phototransistor Q3 and fed to pin 2 of IC µA741 (IC1). Its gain can be varied using potmeter P2. The output of IC µA741 is fed to IC LM386 (IC2) via capacitor (C7) and potmeter P3. The sound produced is heard through the receiver’s loudspeaker. Potmeter P3 is used to control the volume of loudspeaker SPKR (8-ohm, 1W).
Receiver diagram:
 |
| Wireless Audio Power Amplifier Transmitter Circuit Diagram |
Parts:
P1 = 10K
P3 = 10K
P2 = 1M
R1 = 4.7K
R2 = 22K
R3 = 100R
R4 = 10R-1W
R5 = 10K
R6 = 10K
R7 = 15K
R8 = 15K
R9 = 100K
R10 = 680R-1W
R11 = 1K
R12 = 10R-1W
C1 = 220uF-25V
C2 = 220uF-25V
C3 = 10uF-25V
C4 = 220uF-25V
C5 = 220uF-25V
C6 = 100nF-63V
C7 = 100nF-63V
C8 = 100nF-63V
C9 = 100nF-63V
D1 = Red LED
D2 = IR LEDs
D3 = IR LEDs
Q1 = BC547
Q2 = BD140
Q3 = L14F1
IC1 = uA741 Opamp
IC2 = LM386
J1 = Audio input Jack
T1 = Audio Transformer
SPKR = 1W-8ohm
Subscribe to:
Posts (Atom)