Showing posts with label circuit. Show all posts
Showing posts with label circuit. Show all posts
Monday, November 17, 2014
Car Wireless Alarm Circuit Diagram
This FM radio-controlled anti- annexation anxiety can be acclimated with any agent accepting 6- to 12-volt DC accumulation system. The mini VHF, FM transmitter is adapted in the agent at night back it is anchored in the car balustrade or car park. The receiver assemblage with CXA1019, a distinct IC-based FM radio module, which is advisedly accessible in the bazaar at reasonable rate, is kept inside. Receiver is acquainted to the transmitters frequency. Back the transmitter is on and the signals are actuality accustomed by FM radio receiver, no hissing babble is accessible at the achievement of receiver. Appropriately transistor T2 (BC548) does not conduct. This after-effects in the broadcast disciplinarian transistor T3 accepting its advanced abject bent via 10k resistor R5 and the broadcast gets energised.
Back an burglar tries to drive the car and takes it a few metres abroad from the car porch, the radio articulation amid the car (transmitter) and anxiety (receiver) is broken. As a aftereffect FM radio bore gene-rates hissing noise. Hissing AC signals are accompanying to broadcast switching circ- uit via audio transformer. These AC signals are rectified and filtered by diode D1 and capacitor C8, and the consistent absolute DC voltage provides a advanced bent to transistor T2. Appropriately transistor T2 conducts, and it pulls the abject of broadcast disciplinarian transistor T3 to arena level.
The broadcast appropriately gets de-activated and the anxiety affiliated via N/C contacts of broadcast is switched on. If, by chance, the burglar finds out about the wireless anxiety and disconnects the transmitter from battery, still alien anxiety charcoal activated because in the absence of signal, the receiver continues to aftermath hissing babble at its output. So the burglar anxiety is fool-proof and awful reliable.
Sunday, November 16, 2014
Reducing Treble tone circuit
Treble reducer circuit above is an example of a simple circuit and is suitable to be used as experimental material and analysis of the workings of the circuit.
As I mentioned earlier the bass reducer series, this series actually has the same working principles with a series of bass reducer. Where these circuits utilize capacitors nature of the charge and discharge. The difference of the damping function obtained from the difference of the capacitor. If the series bass reducer series capacitors are mounted on the op-amp input lines, while in this treble reducer series capacitors are mounted parallel with the strengthening of the op-amp prisoners. Installation of this circuit has a parallel in the work analysis in contrast with the installation of the series on a series of bass reducer. The difference is that the installation of the series, so we URLs that are easy to understand how a wire working capacitors for high frequency signal, so with high frekuesni so automatic signal to be passed to the output terminal by a capacitor. But if we put a parallel between the output capacitor with the terminals, then automatically because the capacitor is considered as a wire so the voltage on the capacitor is near 0 volts, so the output voltage will also follow the voltage on the capacitor because they connect parallel. As with the low frequency signal, the capacitor is considered open and makes voltage wire that fell to him is to approach the input voltage. To understand how the capacitor can be regarded as a wire or an open switch I mentioned in my post about the working principles of capacitors and a series of bass reducer.
Indeed, when examined in detail, not only the capacitors that play a role here but the component resistors and op-amp also affect. But I can confirm that the main function is performed by a capacitor reduction. Series resistors are intended to be installed that will flow into the capacitor can be adjusted so that it influences the charge and discharge the capacitor will make the appropriate damping.
Take a look at the picture above the treble reducer circuit and also the image output signal. There are two function generator as input and has a signal with different frequencies. The first signal of amplitude 1 volt and low frequencies, the two signals with an amplitude of 1 volt and with high frequency. At the time of our input select switch position to the relationship with the input low frequency signal, the signal output will be nearly equal to the input signal such as no change. Whereas if we switch position to link high-frequency input signal then the output signal amplitude will be damped near 0 volts.
Example treble reducer circuit is very simple and can you develop more in accordance with the desires and your needs. At least with understanding the working principle of this circuit we can apply a time when we are required to perform the function of damping trebele.
Friday, November 14, 2014
INFRARED IR SENSOR DETECTOR CIRCUIT
The circuit shows that the output of IC1 555 IC, which is designed for a duty cycle of 0.8mSec, with a frequency of 120Hz and 300 mA peak current, is used to drive the infrared LED, D1.From the connection it is clear that the diodes D1 and D2 are on the same line, just a few centimeters apart, on the breadboard. Thus diode D2 receives the infra-red output from the diode D1.The diode signal, which is given to the inverting terminal of the op-amp IC LM 358 gets amplified and its peak is detected by diode D4 and capacitor C4.The forward voltage produced by diode D4 is compensated by diode D3 with R5 and R6.According to the distance between the infra-red transmitter and receiver, a proportional DC voltage is fed to the inverting input of IC2.According to the output of the comparator the LED is turned ON and OFF and this is detected by the transistor Q1.Thus the relay is driven according to the output of Q1.The comparator output is set according to the value of the pot.
This circuit is mainly used for liquid level detection or proximity detection. It operates detecting the distance from the target by reflection of an infra-red beam. The biggest advantage of this circuit is that there is no physical contact with the liquid whose level is to be measured. The range is set by adjusting the pot. Range can vary, depending on infra-red transmitting and receiving LEDs used and is mostly affected by the color of the reflecting surface. Black surfaces lower greatly the device’s sensitivity.
Infrared Sensor Circuit Diagram
Notes
Use a good quality regulated power supply .The sensor diodes must not be subjected directly to other light sources.
Parts List
- Resistance R1 10K(4W)
- Resistance R2, R5, R6, R9 1K(4W)
- Resistance R3 33R(4W)
- Resistance R4, R8 1M(4W)
- Trimmer Cermet R7 10K
- Resistance R10 22K(4W)
- Capacitance C1, C4 1 uF(63V)
- Capacitance C2 47pF(63V)
- Capacitance C3, C5, C6 100uF(25V)
- Diode D1 IR LED
- Diode D2 IR Photo-Diode
- Diode D3, D4 1N4148(75W/150mA)
- Diode D5 LED
- Diode D6, D7 1N 4002
- PNP Transistor Q1 BC 558(45V/800mA)
- Timer IC IC1 NE 555
- IC 2 LM358
- IC 3 7812
- Relay SPDT(2A/220V)
- J1 Two ways output socket
Thursday, November 13, 2014
TT6061A and TT8486A sensitive touch light dimmer circuit with explanation
Using a CMOS IC TT8486A TT6061A you can build a very simple dimmer circuit which can be used to control intensity of an incandescent lamb by simply touch a contact . This electronic touch dimmer circuit can increase the light intensity of incandescent lamps in three steps.
Initially, when mains switch is ‘on,’ the bulb is ‘off’. Now, if you touch the touch plate, the bulb glows dimly. On second touch, the bulb gives medium light. At the third touch, the bulb is driven fully and another touch puts off the light.
This sensitive touch light dimmer circuit uses minimum external components and can be used for 110V or 220V AC by simply changing some external components . For touch plate, you can use a simple copper plate of 1cm×1cm (a small piece of PCB) or even the end of the lead wire. Touch plate is coupled to the touch detector through 1000pF, 2kV capacitors C4, C5 connected in series. Internally IC TT6061A’s touch signal is connected to the counter/ decoder via a resistor and clock input CK is connected to the counter/decoder via a frequency generator.
Line frequency signal is taken through R4 at pin 2 of IC TT6061A. At zero crossing, the triac (BT136) triggers to drive a 200W bulb.![]( "TT6061A")
For 220 volts usage you’ll need to change R1 510K TO 620K ( FOR 60HZ CHANGE TO 50HZ ) , R2 20K/1W TO 40K/2W ( FOR 110V CHANGE TO 220V ) and R6 1M TO 1.5M ( FOR 110V CHANGE TO 220V ) and also you can add an additional capacitor in series with the C4 and C5 ( capacitor used must be the same type an value ) .
S: electroniq.net/other-projects/tt8486a-tt6061a-sensitive-touch-light-dimmer.html
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Initially, when mains switch is ‘on,’ the bulb is ‘off’. Now, if you touch the touch plate, the bulb glows dimly. On second touch, the bulb gives medium light. At the third touch, the bulb is driven fully and another touch puts off the light.
This sensitive touch light dimmer circuit uses minimum external components and can be used for 110V or 220V AC by simply changing some external components . For touch plate, you can use a simple copper plate of 1cm×1cm (a small piece of PCB) or even the end of the lead wire. Touch plate is coupled to the touch detector through 1000pF, 2kV capacitors C4, C5 connected in series. Internally IC TT6061A’s touch signal is connected to the counter/ decoder via a resistor and clock input CK is connected to the counter/decoder via a frequency generator.
Line frequency signal is taken through R4 at pin 2 of IC TT6061A. At zero crossing, the triac (BT136) triggers to drive a 200W bulb.
This light dimmer circuit require a 6.8 volts power supply, which is taken directly from mains through resistors R2, diode D1, capacitor C2, and zener diode and fed to power-input pin 3 of the IC. Capacitors C4, C5 connected between touch input pin 4 and touch plate remove the shock potential from the touch plate, so do not replace these capacitors with a single capacitor or with a capacitor of a lower voltage rating.
Te circuit diagram shown here is just for 110 volts ac , if you want to use this touch sensitivity light dimmer for 220 volts AC , you need to chance some components value .For 220 volts usage you’ll need to change R1 510K TO 620K ( FOR 60HZ CHANGE TO 50HZ ) , R2 20K/1W TO 40K/2W ( FOR 110V CHANGE TO 220V ) and R6 1M TO 1.5M ( FOR 110V CHANGE TO 220V ) and also you can add an additional capacitor in series with the C4 and C5 ( capacitor used must be the same type an value ) .
S: electroniq.net/other-projects/tt8486a-tt6061a-sensitive-touch-light-dimmer.html
Tuesday, November 11, 2014
FM booster schematic circuit with explanation
A low-cost circuit of an FM booster that can be used to listen programs from distant FM stations clearly. The circuit comprises a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570 ( C2570).
This FM booster circuit is constructed using few common components ( not require some special components ) and provide a very good gain .
To calibrate this circuit you need to adjust input/output trimmers (VC1/VC2) for maximum gain.
Input coil L1 consists of four turns of 20SWG enamelled copper wire (slightly space wound) over 5mm diameter former.
It is tapped at the first turn from ground lead side. Coil L2 is similar to L1, but has only three turns.
Both of the trimmers are 22pF value .This FM radio signal booster needs to be powered by a 12 volts DC power supply
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more at: electroniq.net/radio-frequency/fm-booster-schematic-circuit.html
Saturday, November 8, 2014
Wednesday, November 5, 2014
Circuit Guards Amplifier Outputs Against Overvoltage
A universal requirement for automotive electronics is that any device with direct connections to the wiring harness must be able to withstand shorts to the battery voltage. Though brutal, this requirement is necessary for reliability and for safety. One example of the need for this protection is an audio amplifier that produces indicator noises in the automotive interior. Though operating from a voltage of 3.3 or 5V, which is lower than the battery voltage, the amplifier must be able to stand off the full battery voltage.
Circuit Diagram :
![amplifier]()
Figure 1 : This output circuit provides continuose protection against overvoltge faults
You can also use a protection network appropriate for these amplifiers for other automotive circuits (Figure 1). A dual N-channel MOSFET disconnects the amplifier’s outputs from the wiring harness in response to a high-voltage condition on either output. The MOSFETs, Q1A and Q1B, are normally on; zener diode D4 and its bias components drive the MOSFETs’ gates to approximately 11V. Dual diode D3 provides a diode-OR connection to the dc voltage on each output, thereby producing a voltage that controls the output of shunt regulator IC2. The circuitry protects IC1, a 1.4W Class AB amplifier suitable for audible warnings and indications for the automotive electronics.
During normal operation, the amplifier outputs’ dc components are at one-half of the VCC supply—2.5V in this case, for which VCC is 5V. The 11V gate drive fully enhances the MOSFETs, and the shunt-regulator output is off because its feedback input, Pin 5, is below its internal 0.6V threshold. If either output exceeds 5V, current flows through D3 into the R5/R6 divider, pulling the feedback terminal above its threshold. The shunt-regulator output then pulls the MOSFET-gate voltage from 11V almost to ground, which blocks high voltage from the amplifier by turning off the MOSFETs. The MOSFETs easily withstand the continuous output voltage, and the circuit returns to normal operation when you remove the short. Because the circuit does not respond instantaneously, zener diodes D1 and D2 provide protection at the beginning of a fault condition.
![Figure]()
Figure 2. In Figure 1, one of U1s two audio outputs (top trace) is protected when its external terminal accidentally contacts an 18V supply voltage (2nd trace).
The waveforms of Figure 2 represent an operating circuit. One of the amplifier’s outputs (Trace 1) is a 1-kHz sine wave biased at a dc voltage of 2.5V. Trace 2 is the signal on the wire harness. It also starts as a 1-kHz sine wave biased at a 2.5V-dc voltage, but, at 200 µsec, it shorts to an 18V supply. Trace 3 is the shunt regulator’s output, initially biased at 11V but pulled to ground in response to the overvoltage condition. Trace 4 is current in the wire harness. Initially a sine wave, this current drops to zero in response to the overvoltage condition.
The components in Figure 1 optimize this circuit for 5V operation. For other voltages, you can adjust the R5/R6 resistor values. The shunt regulator must be able to function in saturation and, therefore, requires a separate supply pin in addition to the shunt output pin. The circuit repeatedly withstands 28V shorts without damage.
Circuit Diagram :
Figure 1 : This output circuit provides continuose protection against overvoltge faults
During normal operation, the amplifier outputs’ dc components are at one-half of the VCC supply—2.5V in this case, for which VCC is 5V. The 11V gate drive fully enhances the MOSFETs, and the shunt-regulator output is off because its feedback input, Pin 5, is below its internal 0.6V threshold. If either output exceeds 5V, current flows through D3 into the R5/R6 divider, pulling the feedback terminal above its threshold. The shunt-regulator output then pulls the MOSFET-gate voltage from 11V almost to ground, which blocks high voltage from the amplifier by turning off the MOSFETs. The MOSFETs easily withstand the continuous output voltage, and the circuit returns to normal operation when you remove the short. Because the circuit does not respond instantaneously, zener diodes D1 and D2 provide protection at the beginning of a fault condition.
The waveforms of Figure 2 represent an operating circuit. One of the amplifier’s outputs (Trace 1) is a 1-kHz sine wave biased at a dc voltage of 2.5V. Trace 2 is the signal on the wire harness. It also starts as a 1-kHz sine wave biased at a 2.5V-dc voltage, but, at 200 µsec, it shorts to an 18V supply. Trace 3 is the shunt regulator’s output, initially biased at 11V but pulled to ground in response to the overvoltage condition. Trace 4 is current in the wire harness. Initially a sine wave, this current drops to zero in response to the overvoltage condition.
The components in Figure 1 optimize this circuit for 5V operation. For other voltages, you can adjust the R5/R6 resistor values. The shunt regulator must be able to function in saturation and, therefore, requires a separate supply pin in addition to the shunt output pin. The circuit repeatedly withstands 28V shorts without damage.
Monday, November 3, 2014
Protection For Telephone Line Circuit
A long time ago when telephones were so simple almost nothing could go amiss from an electrical point of view, Telecom operators installed surge protection on all telephone lines exposed to storm risks. Paradoxically, now that we are hooking up delicate and expensive equipment such as telephones filled with electronics, fax machines, (A)DSL modems, etc., this protection has disappeared.
However, if you have the good fortune to live in the countryside in a building served by overhead telephone lines, there’s an obvious risk of very high voltages being induced on the lines during thunderstorms. While we have lost count today of all of the modems, fax machines and other telephones that have been destroyed by a ‘bolt of lightning’, surprisingly you only have to invest a few pounds to get a remarkably efficient protection device like the one we are proposing here.
During a storm, often with lightning striking near a telephone line, the line carries transient voltages up to several thousands of volts. Contrary to the HV section of television sets or electrical fences, on which practically no current is running, in the case of lighting striking current surges of thousand of amps are not uncommon. To protect oneself from such destructive pulses, traditional components are not powerful or fast enough.
As you can see on our drawing, a (gas-filled) spark gap should be used. Such a component contains three electrodes, insulated from each other, in an airtight cylinder filled with rare gas. As long as the voltage present between the electrodes is below a certain threshold, the spark gap remains perfectly passive and presents an impedance of several hundreds of MW. On the other hand, when the voltage rises above this threshold, the gas is very rapidly ionized and the spark-gap suddenly becomes a full conductor to the point of being able to absorb colossal currents without being destroyed.
Protection Circuit Diagram For Telephone Line :
The one we are using here, whose size is of the same magnitude as an ordinary one watt resistor, can absorb a standardized 5,000 amps pulse lasting 8/20 ms! Since we are utilizing a three-electrode spark gap, the voltage between the two wires of the line or between any wire and ground, cannot exceed the sparking voltage, which is about 250 volts here. Such protection could theoretically suffice but we preferred to add a second security device made with a VDR (GeMOV or SiOV depending on the manufacturer), which also limits the voltage between line wires to a maximum of 250 volts.
Even if this value seems high to you, we should remember that all of the authorized telephone equipment, carrying the CE mark must be able to withstand it without damage. This is not always the case however with some low-end devices made in China, but that’s an entirely different problem. Since pulses generated by lightning are very brief, the ground connection of our assembly must be as low-inductance as possible.
It must therefore be short, and composed of heavy-duty wire (1.5 mm2 c.s.a. is the minimum). If not, the coil, composed of the ground connection, blocks the high frequency signal that constitutes the pulse and reduces the assembly’s effectiveness to nothing. Finally, please note that this device obviously has no effect on the low frequency signals of telephones and fax machines and it does not disturb (A)DSL signals either.
Sunday, November 2, 2014
MOSQUITO REPELLENT ELECTRONIC CIRCUIT DIAGRAM
MOSQUITO REPELLENT ELECTRONIC CIRCUIT DIAGRAM
It uses IC CD4047 to control the buzzer timing utilizing resistor and capacitor. When the voltage passing through the transistor, the buzzer would sound.
Variable resistor R1 : 10K ohm
Polar capacitor C2 : 4.7 nF/16V
Capacitor C3 : 22uF
IC1 : CD4047
NPN transistor Q1-Q2 BC547
PNP transistor Q3-Q4 BC557
Buzzer K1 : Tweeter 8 ohm
Power supply : 12V
Friday, October 31, 2014
Microphone FM Transmitter Wireless Two Transistors Circuit
Microphone FM Transmitter Wireless Two Transistors Circuit
Please be warned if operating this circuit might violate the regulation of your country, because this FM transmitter circuit radiate strong radio frequency to the environment. This wireless microphone is very sensitive, pick up every sound in the 20m radius, and transmit the radio signal up to 2 kilometers in open air. The first transistor (Q1) is the pre-amplifier for the microphone, and you can ommit this circuit if you don’t want to transmit the sound picked up by the mic, for example you can can connect your mp3 player directly to C1. The core of this FM transmitter circuit is Q2, a modified Collpits oscillator that the frequency is determined by L1, C4, C6, and the transistor’s internal base-emitter capacitance. The antenna use 1/16 wave length to compromize between the efficiency and the size.
If you want the microphone to be less sensitive, you can replace the R1 by a higher resistor, try 10k or 22k, and this might overcome the feedback problem if you use this wireless microphone FM transmitter for a public address system.
If you want the microphone to be less sensitive, you can replace the R1 by a higher resistor, try 10k or 22k, and this might overcome the feedback problem if you use this wireless microphone FM transmitter for a public address system.
Transistor Inverter circuit 12V to 220V 100W
This circuit power Inverter 100W, it easy and good ideas. When use the electric appliances that want 220V AC 50HZ, which have small-sized about 100Watt not exceed. By when you apply outside home, as a result have to have Mini power inverter about 100Watt, perform modify from work electricity forces of battery 12V give tall fair the work.
If you are New user electronics or want to economize or want to build electronics project use by oneself. I begs for to advise this circuit , because it uses , transistor number BC557 or the number replaces, perform oscillator generator. Then have power transistor 2N3055 numbers perform to drive coil transformer for converter voltage give tall go up 220V AC 50HZ at the electric power about 100 watt not exceed. When apply to transformer about 2A-3A.
Thursday, October 30, 2014
Mono to Stereo Audio Signal Circuit Converter
This circuit is used to convert a mono audio signal into a stereo signal that can be panned between the left and right channel by a 0-10V control signal, it is intended for analog synthesizer systems.
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| Circuit Convert Mono to Stereo Audio Signal Schematic |
Wednesday, October 29, 2014
Low voltage DC motor speed control circuit using TDA7274
Low voltage DC motor speed control circuit using TDA7274
Description.
Here is the circuit diagram of a low voltage /low power DC motor speed controller based on the IC TDA 7274 from ST Microelectronics. The IC TDA 7274 is a monolithic integrated DC motor speed controller intended for low voltage/ low power applications. Built in internal voltage reference voltage, wide input voltage range (1.8 t0 6V), high linearity, 700mA output current, excellent temperature stability etc make this IC well suitable for almost all low power DC motor speed control applications.
The motor to be controlled is connected between pin3 (Vs) and pin4 (output) of the IC. Resistor network comprising of R1, R2, and R3 is the section that deals with the speed control. Control pin (pin8) of the IC is connected to the junction of R2 and R3 and the speed of the motor varies linearly according to the position of POT R3. Capacitor C1 rectifies the fluctuations in motor speed and capacitor C2 cancels the motor spikes.
Here is the circuit diagram of a low voltage /low power DC motor speed controller based on the IC TDA 7274 from ST Microelectronics. The IC TDA 7274 is a monolithic integrated DC motor speed controller intended for low voltage/ low power applications. Built in internal voltage reference voltage, wide input voltage range (1.8 t0 6V), high linearity, 700mA output current, excellent temperature stability etc make this IC well suitable for almost all low power DC motor speed control applications.
The motor to be controlled is connected between pin3 (Vs) and pin4 (output) of the IC. Resistor network comprising of R1, R2, and R3 is the section that deals with the speed control. Control pin (pin8) of the IC is connected to the junction of R2 and R3 and the speed of the motor varies linearly according to the position of POT R3. Capacitor C1 rectifies the fluctuations in motor speed and capacitor C2 cancels the motor spikes.
The circuit can be assembled on a Perf board.
Power supply Vs can be anything between 1.8V to 6V and it must be selected according to the rating s of the motor.
Maximum output current capacity of this circuit is 700mA.
TDA7274 must be mounted on a holder.
POT R3 can be used to vary the motor speed
RGB To Color Difference Converter Diagram Circuit
The circuit diagram shows two LT1398’s from Linear Technology used to create buffered color-difference signals from RGB (red-green-blue) inputs. In this application, the R input arrives via 75Ω coax. It is routed to the non-inverting input of amplifier IC1a and to 1.07-kΩ resistor, R8. There is also an 80.6-Ω termination resistor R11, which yields a 75-Ω input impedance at the R input when considered in parallel with R8. R8 connects to the inverting input of a second LT1398 amplifier (IC1b), which also sums the weighted G and B inputs to create a –0.5Y output.
![RGB]()
Yet another LT1398 amplifier, IC2a, then takes the –0.5Y output and amplifies it by a gain of –2, resulting in the +Y output. Amplifier IC1a is configured for a non-inverting gain of 2 with the bottom of the gain resistor R2 tied to the Y output. The output IC1a thus results in the color-difference output R–Y. The B input is similar to the R input. Here, R13 when considered in parallel with R10 yields a 75-Ω input impedance. R10 also connects to the inverting input of amplifier IC1b, adding the B contribution to the Y signal as discussed above.
![PSU]()
Amplifier IC2b is configured to supply a non-inverting gain of 2 with the bottom of the gain resistor R4 tied to the Y output. The output of IC2b thus results in the color-difference output B–Y. The G input also arrives via 75-Ω coax and adds its contribution to the Y signal via resistor R9, which is tied to the inverting input of amplifier IC1b. Here, R12 and R9 provide the 75Ω termination impedance. Using superposition, it is straightforward to determine the output of IC1b. Although inverted, it sums the R, G and B signals to the standard proportions of 0.3R, 0.59G and 0.11B that are used to create the Y signal. Amplifier IC2a then inverts and amplifies the signal by 2, resulting in the Y output. The converter draws a current of about 30mA from a symmetrical 5-volt supply.
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FM 250mW transmitter electronic Circuit diagram
A very simple FM transmitter electronic project can be designed using this circuit diagram . This FM transmitter electronic project works in FM band and it has a transmission power around 250mW ( thing that make it to work at above hundred meters ) . This FM transmitter electronic circuit is very simple and is based on some common transistors and electronic parts .
T1 transistor can be a BC107, BC171 or equivalent , and is used as an small audio preamplifier that amplify the audio signal from the microphone . Adjusting the R2 variable resistor, audio signal level from the input ( microphone ) can be adjusted until will be delivered to the T1 preamplifier (an over amplified signal applied to T1 can produce an overmodulation) . From T1 , signal is delivered to T2 which form an Hartley oscillator (frequency of this oscillator depends of C8,C9 and L1) .
The transmitter frequency oscillator works in FM band 87.5-108 MHz and can be set , adjusting C8 capacitor and L1 coil . L1 coil must have four turnings on a 0.8-1 mm cylinder support with a 6 mm diameter (space between each wire must be around 1 mm ) .
Antenna used for this project can be a simple telescopic antenna or a 60-70 mm Cu wire .
This electronic project can be powered from a wide range input voltage from 9 to 12 volts Dc ( but can be used even a 18 volts DC .
T1 transistor can be a BC107, BC171 or equivalent , and is used as an small audio preamplifier that amplify the audio signal from the microphone . Adjusting the R2 variable resistor, audio signal level from the input ( microphone ) can be adjusted until will be delivered to the T1 preamplifier (an over amplified signal applied to T1 can produce an overmodulation) . From T1 , signal is delivered to T2 which form an Hartley oscillator (frequency of this oscillator depends of C8,C9 and L1) .
Antenna used for this project can be a simple telescopic antenna or a 60-70 mm Cu wire .
This electronic project can be powered from a wide range input voltage from 9 to 12 volts Dc ( but can be used even a 18 volts DC .
Monday, October 27, 2014
Sunday, October 26, 2014
LM1875 80W audio power amplifier Diagram Circuit
A very simple high efficiency 80W audio power amplifier project can be designed using the LM3875 power audio IC . LM3875 is a high-performance audio power amplifier capable of delivering 56W of continuous average power to an 8Ω load with 0.1% THD+N from 20Hz to 20kHz .
By connecting two LM39875 audio IC in bridge mode this audio power amplifier will deliver 80 watt of output power into an 8 Ohm load. The LM3875 IC devices should be suitably heatsinked.
As you can see in the circuit diagram , this power audio amplifier require few external electronic parts .
The LM3875 maintains an excellent signal-to-noise ratio of greater than 95dB(min) with a typical low noise floor of 2.0μV.
This 80W audio power amplifier module accepts a wide range input voltage from 20 up to 84 volts, but typically is recommended ( for this circuit ) a dual +/-25 volts DC power supply .
Some features of this 80W audio power amplifier project based on the LM1875 IC are :
output protection from a short to ground or to the supplies via internal current limiting circuitry ,output over-voltage protection against transients from inductive loads ,supply under-voltage protection .
Saturday, October 25, 2014
Stereophonic circuit with TDA7088T
There are two signals that are directed at the so-called FM transmitter the coder (coding). Multiplexing Mpx signal has been contained, two left signals and right indirectly. Frequency modulation of a transmitter carried by the signal Mpx. The receiver output signal is obtained on Mpx and FM detector is then passed to the decoder. At the decoder do the opposite with the coder in the transmitter, because at this level produced two signals L and D.
Signal is amplified by audio amplifier dientik two, then reproduced through two speakers are the same. Now listeners can heard coming from the left half the loudspeaker is placed on the left and right half of which is placed on the right side. Situation amid the orchestra will be equal to that of the second lordspeaker reproduced, made an impression on the listener as if there.
The third loudspeaker placed midway between the left and right. Based on all these listeners have a picture of the layout space, which is significantly increased total musical impression. Electronic circuits of the portable stereophonic radio receiver with headphones reproduction, made by the IC TDA 7088T is shown in Figure the above. This is a practical embodiment of the receiver with TDA7040T decoder and two audio amplifier with TDA7050T IC.
Choke (coils) L3, L4 and L5 are HF coil allows the headphone cable is used as a receiving antenna. this fulfilled by connecting one contact of the plug-in headphones, through a 10 pF capacitor at the point where the output of the antenna is connected. Coil has a significant barrier to the signal station, preventing ground connection through capacitor 47 mF or through the TDA7050T output.
Friday, October 24, 2014
3 Band Tone Control Circuit
3 Band Tone Control circuit uses an op-amp as an amplifier end. Tone Control circuit is a regulator of tone bass, midrange and treble or 3 band called because it can set the three tones. Filter circuit is applied to the series of "Tone Control 3 band" This type baxandal like the title of this article.
Results filtering regulator tone or tone control baxandal type is good, because there is no signal level is wasted directly into the ground. Range frequency tones generated from Tone Control 3 band was determined by the configuration of the R and C of the filter section baxandal. As an amplifier on Tone Control The set of three band use traditional IC LF351 has slewrate high and high input impedance. For more details, series 3 Band Tone Control as follows.
Figure Series 3 Band Tone Control
Wednesday, October 22, 2014
Flip Flop Led Circuit
Flip flop circuit is a series of free runing multivibrator given the burden of LEDs on each side of the transition changes its output signal. Flip flop circuit with LEDs is quite simple, that is prepared with 2 units and 2 units of 2N3904 transistor circuit tank circuit composed by the RC circuit.
LED indicators signal a change that is placed on each side of the flip flop will be lit in turn by the fire and extinguished the same as the charge and discharge capacitor. Flip flop circuit is quite simple as shown in the picture below.
Flip Flop LED series
The working principle is the flip flop over when the series voltage source is given then the 10uF capacitor will be charged through R 470 and the LED will then be forwarded to triger the transistor base so that the transistor will turn ON and LEDs. this occurs alternately on each side, so that the LED light will illuminate in turn as well.
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