Circuit Wiring Solution: 2014

Friday, December 12, 2014

Dual zone alarm schematic

This brilliant circuit shows a two-zone alarm - with automatic exit, entry and siren cut-off timers.It can be triggered by the usual types of normally-closed input devices - such as magnetic reed contacts - foil tape - PIRs etc.

The circuit will work at anything from 9 to 15-volts. All you need do is select a siren, buzzer and relay to suit the voltage you want to use.

Simple DC DC Converter

This schematic shows you how to build a dc-dc schematic.Here's a DC to DC circuit put together just from parts found on the test-bench. All it took was two transistors, two resistors, an audio transformer, a bridge and two caps. It may not be the ultimate in performance, but it does work.

The key to how it works is the transformer. As you can see, two transistors drive the transformer primary with the base drive for each coming from the collector of the other.When power is applied, suppose Q1 turns on a few nanoseconds faster than Q2.

Metal Detector Schematic

Simple Metal Detector - Theory and schematic provided by HobbyHour
Balance Metal Detector - Each coil modifies the frequency of the adjacent oscillator through mutual coupling
Simple Metal Detector - Used one 40106 hex Schmitt inverter IC, a capacitor and a search coil
Metal Detector-1 - A fun metal detector to find coins at the beach
One Coil Induction Metal Detector - Offered induction type metal detector is all-purpose
Coil Coupled Operation Metal Detector - made from readily obtainable component

Thursday, December 11, 2014

Adjustable Lab Power Supply

Make your own lab power supply complete with adjustable voltage and constant current source. Using single IC (LM324)

Thursday, November 20, 2014

Voltage to frequency converter

Changing the voltage to frequency scale in the design of an electronic device is sometimes necessary. The series of articles voltage to frequency converter with the XR 4151 is one jawabanny. Voltage to Frequency converter circuit with the XR 4151 is the idea of time in college, when there are projects to create a tool to hatch chicken eggs. It will be my neighbor also write articles incubators chicken egg-based microcontroller AT89C2051 (tempoe doeloe). Maybe there are friends who still remember to this project. Back to the topic of voltage to frequency converter circuit with the XR 4151. IC XR 4151 is a major component of voltage to frequency converter (Voltage to Frequency Converter).

Fig circuit voltage to frequency converter with the XR 4151

From voltage to frequency converter circuit with XR 4151 on the input signal circuit is a DC voltage level. IC XR4151 on voltage to frequency converter circuit serves to convert the voltage level coming into form in the development of the frequency change, where the output frequency range of voltage to frequency converter with the XR 4151 is proportional to the voltage level input voltage to frequency converter circuit with this 4151 XR.

Electricity Power Saver

Do you know how to work his usual power saving devices in the market is shaped like a dry battery with a plug into an outlet?. Actually you can create your own tool with much better quality with much cheaper price.
Because of the way it works is to reduce the magnitude from cosine curve AC current that will be read on the gauge kilometer. Device work if there is air conditioning load passes through a coil of wire sensors to measure the AC current which is being passed.

Power Saver Circuit

A very influential component in the AC circuit is a capacitor and inductor. Therefore we need to filter the AC current before it enters our home electricity network. Obviously we did not perform the act of theft of electricity, and this tool will not be detected by the device are as follows . How to installation, Here I would include a scheme of the circuit which will be installed close to the mile. The closer, the more optimal the way it works, use good quality capacitors, for security MCB here, serves to prevent the occurrence of shorting out due to damage to the capacitor. Then Enter in box or plastic box which is strong enough. Better capacitor in the cast by GIPs or cement, so that power is wasted heat well.

Wednesday, November 19, 2014

Building a radio station

Requires us to make things systematically and efficiently, because time is very valuable to us, then some of the advances in technology has been applied in various fields, including education, because this is where all the technological advances developed.Lots of technology is rapidly expanding in our country today. With technology growing by leaps and bounds this is what will make the work more systematic and efficient.Based on our technological advances and his friends create a system are related to the Electronics course, we propose the same faculty to develop a community tool. We got a second job in four semesters, which makes the FM transmitter.

Departing from hobby assembling electronic items, we try to assemble a mini-power transmitter that can emit a short signal of approximately 100 meters with power (power) 5 watts. This is a pilot who later became 12 watts. With 12 watts of power, radio broadcasts to reach a village.

1.2 Formulation of ProblemProblems are handled from this lab assignment is to create and analyze the quality of an FM transmitter to get the data at test point 1, point 2 test, test point 3 and the exact frequency as desired.Things are of practical tasks is restricted only to analyze the quality of a transmitter and retrieve data from an existing test point.

1.3 LimitationsProblems to be addressed in this lab assignment is limited to some of the following:1 • Retrieving data from the frequency and calculate TP 1 to TP 3.2 • Analyze a transmitter in the room, based on measurement data and make conclusions.

1.4 ObjectivesObjectives to be achieved in this task are:A. Students can design and make the circuit in fm transmitter.2. 12 Watt FM transmitter that can be made of appropriate tools and can be marketed.

1.5 MethodologyIn completing this lab assignment, the steps are as follows:1 • Learn about basic electronics concepts and learn concepts about the mechanism of FM modulation.2 • Analyze and conclude the experimental results, and give advice when it is applied to the practical task of the real system.3 • Preparing a report on second semester practicum assignment.

1.6 DiscussionThis book of this lab assignment consists of 5 (five) chapters, in each chapter related to one another, namely:

CHAPTER 1:Provide background on the issues, goals, problems and constraints of the problems discussed in this lab assignment.CHAPTER 2:Provide the theoretical basis to support problem solving in this lab assignment. The basic theory is given include: the mechanism of the tool inused in making the FM transmitter

CHAPTER 3:Planning and manufacture of tools and how each blog diagram contained in FM transmitterCHAPTER 4:Contains the results of calculations and data processing, and analysis resultscalculation.CHAPTER 5:Provide conclusions about the results already obtained and suggestions.CHAPTER IIBASIC THEORY

2.1 Koker

Koker serves to regulate or determine the frequency of the radio transmitter. In koker also Ferrite that serves as a core inductor in addition there is an inductance coil comprising primary and secondary winding. Way of working is to facilitate search koker empty wave. When filling koker in turn to the right to a maximum frequency of the oscillator produce more low. If the FM transmitter lights, turn left up the core koker to hissing on the FM radio signal is lost it will be found a strong and stable.

2.2 Inductor

Coil of wire that is wrapped with a particular matter, in this case to determine the value of the inductor is typically used Q-meter. Inductor serves as an impedance adjustment, so that the output of the impedance can be changed and in accordance with the desired (match).

2.3 Transistor

Transistors have two connections, one of which is the emitter and the other base and collector. Because this is a transistor as two diodes. ransistor C1970 type normally used to raise the voltage 0.8 to 1 watt, I think it was in the C1970 study could increase about 8 times.On the C1971 transistor can be coupled directly from the exciter circuit and the voltage of 6.5 to 7 watts or bias raised about 10 times.If the C1970 to C1971 join the output power of about 12 watts or more. (All will be explained in Chapter III)

2.4 ExciterExciter circuit consists of an oscillator and buffer.•  OscillatorTransmitter is the core of an oscillator. To be able to build a good communication system should begin with an oscillator that can work perfectly. In the communication system, the oscillator generates a sine wave is used as the carrier signal. Then the information signal is superimposed on a carrier signal with the modulation process.•  Buffer (Buffer)All types of oscillators require a buffer. Buffer serves to stabilize the frequency and / or amplitude of the oscillator from loading the next level. Usually a buffer consisting of 1 or 2 levels of the transistor amplifier dibias as class A.The heart of the broadcast transmitter FM exciter is located on it. Function of the exciter is to generate and modulate a carrier wave with one or more input (mono, stereo, SCA) in accordance with FCC standards. Which has been modulated carrier wave is then amplified by a wideband amplifier to the level required by the next level.

2.5 BoosterPower amplifier is more popularly known as Booster. Booster is a device mounted radio transmitters attached to and used to amplify radio frequency transmit power in any direction that you want to go. For example, for a transmitter power of 25 watts which include only a single village, Booster is used to transmit power to be 50 to 100 watts so it can besurrounding the district. Boosters are generally small squares connected by cable to the transmitter which he built.Power amplifier is divided into two. First, the power amplifier which amplifies the signal in one cycle, the best signal quality and harmonious. The second, which only reinforces the power amplifier input signal is less than half of the cycle and generate a wave that damaged the same frequency.

2.6 Antenna

Antenna function and simultaneously capture signals radiate radio wave radiation. The antenna is divided into two by the beam, ie• omnidirectional (all directions). This antenna radiates radio waves are equally strong all directions.• Bidirectional (both directions). This antenna radiates equally strong radio waves to only two directions. Two parameters that need to be considered is the polarization of the antenna and its gain. Put simply, an antenna has vertical polarization if the antenna is placed in a position perpendicular to the earth. Antenna with vertical polarization would produce radio waves with vertical polarization as well. In addition to the vertical, some horizontal polarized antenna, when the antenna is positioned parallel to the field of the earth.

2.7 Transmission LineTransmission line is the introduction to the generated power to the transmitter antenna. As an introduction to power, a good transmission line will not reduce the power of delivery and did not radiate, because it is the duty antennas radiate. So that the maximum power transfer occurs, then the transmission line characteristic impedance should also have the same view of resource load. Transmission line characteristic impedance is 300 W common (ribbon cable to the black and white TV), 75 W (on a color TV coaxial cable) and 50W (coaxial cable to the amateur radio equipment).Additional tools are in need in assembling a 12-watt FM transmitter, among which are:

•  Power MeterPower Meter is a tool to measure the wave. On a transmission line that is not worth it, but the waves come rolling waves are reflected. Wave dating from the source to the load direction (from transmitter to antenna), while the reflected wave from the opposite direction (from the antenna to the transmitter). Usually on the Power Meter has two scales, onecame to power and one for the reflected power. The reflected power scale to be smaller than the scale for the future.

•  SWR MeterSWR meter or measuring comparative standing waves are used to measure the ratio of the incident wave and reflected wave. So it is known how a resource commensurate with the burden. The working principle is based on the Power Meter SWR Meter. If there is only one Power Meter measurements, the SWR can be calculated from the incident power (Pf) andthe reflected power (Pr) with the formula:SWR = (OPF + ÖPr) (OPF - ÖPr).

• From the formula, the state equivalent (Pr = O) will be obtained SWR = 1.
• For a state that is not worth going to get SWR> 1.
• For the worst circumstances in which all power is reflected back dating (Pf = Pr) will get the SWR = infinity.

•  Dummy LoadTo be able to broadcast a maximum transmit power, but efficient, it takes a load impedance that is known with certainty as it is called Dummy Load reference. Dummy Load is free from the influence of frequency and can handle the disposal of the transmit power is too great. Dummy Load impedance is usually 50 or 75 Ohm. Dummy Load can be made withput some resistors in parallel in order to obtain the desired resistance and power. Parallelize some resistors minimize the stray inductance of the resistor. For example, can use the carbon resistor 300 Ohm / 2 watt for 6 seeds that are connected in parallel to get the Dummy Load with power of 12 watts and 50 Ohm impedance.

CHAPTER IIIPLANNING AND DEVELOPMENT TOOLS

3.1. PreliminaryTo plan and create a 12 Watt FM transmitter, need to know first about a block diagram of the system, the working system of the circuit isOverall, the calculations and planning.

3.2. System Block Diagram and Figure Series Overall

The picture above shows a block diagram of this system and imageThe overall network is made in full.Transmission System Block Diagram picture as a whole

3.2.1 Block diagram of the image transmitter exciter circuit FM

Picture Exciter Circuit Network consists of exciter oscillator and buffer. In this Exciter Network using the specification of components as follows:•  Koker•  Inductor: L2 = 0.12 micro-Henry, Henry Micro L3 = 0.12, L4 = 0.2 micro-Henry•  Transistor: C930•  Ohm: 5.6 K, 47 K, 33 K•  Babysitter WANTED: 2.2 nF, 100 nF, 18 pF, 20 pF, 5 pF•  trimer: 5-60 pFExciter is a network that produces oscillations, because the exciter are oscillator that acts as a sine wave generator and it will be dimodulasikan. In the oscillator system is also available buffer (buffer) that functions to stabilize the frequency / modulation oscillator amplifier due to the loading process by the next level.

3.2.2 Network Booster (Power Amplifier)

The series of images BoosterIn the Booster circuit uses components withthe following specifications:

•  Inductors: L1 = 0.2 micro-Henry. L2 = 0.2 micro-Henry. 0085 L3 = L4 = 0.04 micro micro Henry Henry. L5 = 0.1 micro-Henry. L6 = 0.2 micro-Henry L7 = 0.2 micro-Henry.

•  Transistor 1970: 10 V VCEIc 0.1 AΒ 10-180

•  trimer: 5-30 pFBooster circuit consists of two levels of transistor amplifiers, each working on a class C, each input and output transistor amplifier circuit is given impedance adjustment.Strengthening of the first transistor using C1970. Strengthening the circuit has a 9.2 dB power gain (8 times), so that from the exciter-power 0.25 W of power generated should be 2 W. In fact the output of this first level of reinforcement produces only 1.75 Watt power, this is due to the loss of matching network circuit.Strengthening of the second level using transistor C1971. The amplifier circuit has a 10dB power gain (10 times). So that the power of the first level of 1.75 W can be strengthened to 17.5 W. In fact strengthening the power of the second level only reached 12.5 Watt.

This is due to the loss of matching network and the limited range ofC1971 transistor. Because the price of the C1971 transistor is relatively expensive it is to use only the C1970 transistor. Therefore, the power generated by the transmitter is not as high as 12 Watt. Because of the heat generated second transistor is large enough then we put enough cooling.

CHAPTER IVTESTING TOOLS4.1

GeneralThis chapter discusses the testing and analysis system that has been made. In general, this test aims to determine if the device has been realized that can be worked in accordance with a predetermined plan specifications. The purpose of the tests performed on the system are as follows:

•  Knowing how the exciter circuit

•  Knowing how the booster circuit

4.2 Testing exciter circuit
•  The purposeTo find out if the oscillator can work well and achieve the desired frequency. And also to determine whether the buffer is running properly.
•  The equipment usedA. Koker2. Inductor3. Transistor4. Resistor5. Trimer6. Dummy Load7. 5 volt power supply8. Multimeter9. Frequency Counter10. PCB
•  The test procedureTest Block DiagramA. Assemble the equipment used in accordance Picture2. Provide 12 volt power supply to the exciter circuit3. Switch the exciter circuit to get the most power in large4. Calculate the voltage at TP 1, TP 2 and, TP 35. Observe the output (at V output)
•  The test resultsThe test results are shown in Table. the following:Exciter circuit Testing ResultsTest Results PointA 0.6V2 0.6V3 11.75 V
4.3 Testing a series of booster
•  The purposeTo gain greater power and also increase the distance range of further emission up to 7-fold.
•  The equipment usedA. Inductor2. Transistor3. Trimer4. Dummy Load5. 12 Volt Power Supply
•  The test procedureTesting Block Diagram Picture Booster:A. Assemble the equipment used in accordance Picture2. Large test circuit voltage that can be accepted3. Observing the output
•  The test resultsThe test results are shown in Table. the following:Booster circuit Testing ResultsTest Results Point4 11,755 11,75

CHAPTER VCLOSING
5.1. ConclusionBased on the test results it can be concluded:
•  In a series of FM transmitters weve made, the power output is only 2 Watt for C1970 transistor used is that only 1 Watt power up
•  FM transmitter that can be made only reach 93 MHz frequency
•  The distance achieved depends on the power emitted by the FM transmitter
5.2 Advice
• If you want to make the transmitter starts with a good oscillator.
• If you want to make a series of FM with a power greater then use the transistor C1971, C1946. the power generated about 25 watts.
• To balance the output of the FM transmitter mounted circuit PLL (Phase Local Loop).

Alkaline battery charger

Alkaline Battery Charger series is special used for alkaline battery charger. Alkaline Battery Charger With this series of alkaline batteries that have been drop (1.3 V) to the Rev back to 1.6 V. LEDs on the circuit this Alkaline Battery Charger will flash during charging process, and will be extinguished when the battery is full. The series also features Alkaline Battery Charger for 9V battery charger. VR 47 Ohm serves to regulate the battery charging current.

Alkaline Battery Charger series on utilizing each side beat AC signal from travo to perform the charging process, which is controlled using a 4 pieces set as the rectifier diodes. In mencharger battere with this series should often be controlled, because this circuit is not equipped with overcharge protection, especially for small-size battery.

3W Stereo Amplifier schematic

3 Watt stereo amplifier circuitusing MAX 7910 IC. The MAX9710 a stereo audio power amplifier IC capable of delivering 3Watts of out put to 4 Ohm loads. MAX9710 can be operated from a single 4.5V to 5.5V power supply , makes it ideal for hand held applications.The IC for 3 Watt stereo amplifier circuit also features thermal overload protection.

Circuit Schematics 3 Watt Stereo Amplifier MAX 7910

3 Watt stereo amplifier circuit

This 3 Watt stereo amplifier circuit is suitable for small power audio devices such as radio sets and portable CD players. 5 V DC power supply is used for powering the 3 Watt stereo amplifier circuit. 6V battery with an IN 4007 diode series to the positive terminal of it can also be used instead of 5 V DC supply. The 3 Watt stereo amplifier circuit will get a supply voltage approximately 5 V after 0.7 V voltage drop across diode.

Tuesday, November 18, 2014

555 timer calculator monostable and astable operation

This 555 timer IC calculator can calculate frequency, duty cycle, and high and low output of timer IC operation on both monostable and Astable. This Calculator script was written by Robert Davis of Goldsmith College

555 timer IC

555 timer Pin number and designation:
pin 1- ground or common pin
pin 2- trigger pin
pin 3- output pin
pin 4- reset pin
pin 5- control pin
pin 6- threshold pin
pin 7- discharge pin
pin 8- positive supply

555 MONOSTABLE OPERATION
Acts as one shot pulse generator of output high duration of T=RC ln(3)

555 timer monostable

R:

C:

T Output High (Seconds) =

555 TIMER ASTABLE OPERATION

555 timer astable operation

This operation has an output of continuous pulses of specified frequency and and duty-cycle.

Triangle Square Wave Generator Using Op Amp

The circuit shows a simple triangle and square wave generator with a common dual operational amplifier LM1558 to produce very low frequencies around 10 kHz. The time interval for one half cycle is about R * C and outs of supply of 10 mA. The amplitude of the triangle can be altered by adjusting the 47K and waveform offset can be eliminated by adding a capacitor in series with the output.

Monday, November 17, 2014

Simple Inverter with Two Transistors

The series below is a simple inverter circuit that will change the voltage of 12v dc to 220v ac, with use drive transistor 32 as its tip.
Inverter circuit is very simple and easy to assemble and is perfect for just starting to learn to assemble electronic circuits, you can use the transformer 2A to produce about 20 watts output. Do not forget to install coolers in its transistors. good luck.

Track the damage capacitors elco with ESR meter

All technicians must have the same experience that the old models of aircraft generally have several common Elco its dry or down in value, mainly found in many brands of china plane. Eco is dry can cause a variety of disorders that are sometimes difficult to trace or even be able to make certain parts do not work at all, especially if used on a circuit that works at such high frequency SMPS (Switch Mode Power Supply) and the horizontal. Elco dry technicians sometimes make headaches and time consuming when you track the damage.

Many technicians get around this problem by directly replacing all existing Elko, the Elko-regardless of whether Elko is corrupt or not. It is generally quite successful. But sometimes the quality is not good substitutes Elko, so the damaged aircraft back after use for some time. Replace all of Elko is also a problem for yourself if the circuit is improved a lot using Elko. The use of ESR-meter proved to be the most appropriate choice to solve the above problems. We suggest that ESR-meter is a must-have tool for every technician after avo-meter.

Using ESR-meter weve made themselves at a cost of less than 50,000 rupiah we recorded a lot of advantages such as:

Elko track damaged by the time more quickly because they do not need to remove the Elko (in-circuit tester) one by one.
Elko only replaced damaged
Can be used to check the quality of new and used Elko. It is certainly advantageous to utilize part of the former ex-change machine pcb. Sometimes the plane is damaged due to repeated just posted a new Elko was poor quality.
Elko that if the check using the ohm-meter sometimes the results are deceptive. Because if you checked with ESR ESR-meter turns his already large.
Can be used to check the flyback is short in the primary coil (between the B + with a pin-pin-collectors), def a short yoke, the power tranfo a short primer.
To find out if re-chargeable batteries are still good. Re-chargeable battery that is damaged ESR was generally higher when compared to a still good.
To keep track of printed lines leaking / short
By comparing the capacitors are still good, ESR-meter can be used to check the value of thousands pf capacitor.

Note:

ESR meter can not be to find Elko leak or short. Fortunately rare short Elko damage.
ESR meter to check the fit only Elko with values ranging 0.47uF and above.

Does ESR it actually?Parameters are generally owned by a Elko understood by engineers is the "maximum working voltage" and "capacitance value". In the real case there are several other parameters such as the "maximum working temperature" (85 or 105 degrees C) and "ESR" (Equivalent Series Resistance).Unless the practice is capacitive in Elko also has the characteristics of "resistive" caused by a combination of resistance to the legs, internal connections, plates and electrolyte. Thus form a resistive characteristic ESR, because if it is portrayed as if such be installed in series with the capacitance of Elko.Ideally, an Elko ESR is zero, but in practice this is impossible.Elko High voltage tends to have larger ESR than the low voltage ElkoElko with small values tend to have higher ESR values greater than Elko.Elko 105 degrees (C) tend to have higher ESR than Elko 85 degrees (C).

What Is the ESR-meter?

ESR meter is a kind of ohm-meter that can be used to measure the amount of "resistance" of Elko. Difference if the ohm-meter using a dc current (direct current) to drive the meter, then use the ESR meter ac (alternating current) with a standard frequency 150Khz. As had been explained that ideally Elko its ESR is zero. But this is not possible in practice. Elko good quality 10uF value is close to zero or more generally.

What is the cause of ESR Elko subject to change.

The first is caused because of the connection quality is poor constituents. It can be found in Elko Elko New and old.
Both are caused due to dry the liquid electrolyte due to evaporate or leak, which can be found at the old Elko. Are the consequences of large ESR Elko turned into?

Consequences of changing the value of ESR Elko

Elko is a working principle can be "in-fill and waste of" electric charge repeatedly. Thus ESR Elko-charging current will be passed this exile repeatedly in accordance with the working frequency of the circuit. And we certainly have understood that if bypassed resistor will generate heat flows in accordance with the magnitude of the current strength through resistance value and the corresponding magnitude. Similarly, the Elko with ESR, the greater the greater the ESR value of the heat arising in Elko, and the higher the frequency the greater the heat generated. This heat can eventually cause the electrolyte evaporates into a gas and seeped out, so the value of Elko will turn down. In the specific cases heat can even make Elko explode.
On a circuit that works at high frequencies Elko should have zero resistance to the high frequency signal. If the ESR of the resistance turned into Elko is no longer zero, and if the resistance value change is large enough to make the workings of the chaotic circuit.

Our experience with the use of ESR meter in the aircraft repair older model (the old plane), the first one we always do is:

Check out all the Elko with ESR-meter at the SMPS, Horizontal and Vertical and immediately replace it if the ESR problem.
Check visually (with a magnifying glass if necessary) solder-solder on the SMPS, the output Horizontal, Vertical output, and the CRT socket pcb and soldering again if there appears a problem or suspicious solder it.
Both of these were able to eliminate the difficulties that may arise and difficult to trace, so the use of ESR meter can shorten repair time.

How to use homemade ESR meter (calibration)

Once the tool is finished
Collect some old Elko is still good. Find Elko pcb traces of the plane, made in Japan or Europe the original (former aircraft engine change) because of generally good quality for use as a reference.
Grouped on the basis of a value less dar 2.2uF, 4.7uF is less than, less than and greater than 10uF 10uF.
Try using the ESR-meter to measure each group, and mark the position of the needle meter on each group
These markers can be used as a reference to the appointment of Elko ESR is still good.
If the meter needle to deviate less from the reference mark, the mean ESR Elko is not good.

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

Simple 110 and 220V AC LED Voltage Indicator

This circuit, designed on request, has proven to be useful to indicate when the voltage in a power supply line is changing from 120V to 240Vac. It can be used in different circumstances and circuits, mainly when an increase in ac or dc supply voltage needs to be detected. D3 illuminates when the line voltage is approaching 120V and will remain in the on state also at 240V supply. On the other hand, D6 will illuminate only when the line voltage is about 240V and will stay on because the latching action of Q1, Q2 and related components. C1, D1 and D2 provide a low dc voltage in the 4.5V - 6V range in order to allow proper operation of latch circuit and LEDs.

Circuit diagram

Parts:

R1_____________470R 1/2W Resistor
R2_____________220K 1/4W Resistor
R3,R7__________470R 1/4W Resistors
R4_______________1K 1/4W Resistor
R5_______________2K2 1/4W Resistor
R6_____________330R 1/4W Resistor
C1_____________330nF 630V Polyester Capacitor
C2______________10µF 25V Electrolytic Capacitor
D1,D2________1N4007 1000V 1A Diode
D3,D6___________LEDs (Color and shape at will)
D4_________BZX79C10 10V 500mW Zener Diode (See Notes)
D5___________1N4148 75V 150mA Diode
Q1____________BC547 45V 100mA NPN Transistor
Q2____________BC557 45V 100mA PNP Transistor

Notes:

D4 value could require some adjustment in order to allow precise switching of the circuit at the chosen voltage. If the case, please try values in the 8.2V - 15V range.
Warning! The circuit is connected to 240Vac mains, then some parts in the circuit board are subjected to lethal potential! Avoid touching the circuit when plugged and enclose it in a plastic box.

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

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

PWM Generator Schematic

PWM waveforms are commonly used to control the speed of DC motors. The mark /space ratio of the digital wave-form can be defined either by using an adjustable analogue voltage level (in the case of a NE555 based PWM generator) or digitally using binary values. Digitally derived PWM waveforms are most often produced by the timer/counter modules in microcontrollers but if you do not want to include amicrocontroller in your circuit it’s also quite simple to generate the signals using discrete logic components. An extension of the circuit shown can pro-duce two PWM waveforms from an 8-bit digital input word. Each signal has 15 val-ues. The 8-bit word can be produced for example from an expansion board fitted in a PC or from an 8-bit port of a processor which does not have built-in PWM capability or from a laptop’s printer port.

Discrete PWM Generator Circuit Diagram

The mark/space ratio is only programmable up to 15/16 rather than 16/16; a binary input of 0000 produces a continuous low on both outputs turning both motors off. Similar circuits often employ a dedicated ‘enable’ input to turn the motors off but it is not necessary in this design.

The diagram shows the circuitry required to produce just one waveform. For the full two channel circuit it is necessary to use an additional 74HC193. The clock signal produced by the HCF4060 generator can be used to drive both channels and the free flip flop in the 74HC74 package can be used for the second channel (the corresponding pin numbers are shown in brackets). Alto-gether the entire two channel circuit can be built using just four ICs.

Wednesday, November 12, 2014

LM331 Voltage to Frequency Converter Datasheet

This LM331 voltage to frequency converter commonly used in circuit for analog to digital conversion, frequency to voltage conversion, linear frequency modulation, and many more. It provides the output pulse train at a frequency properly to the applied input voltage and can operate at 4.0V power supply and be changed output frequency from 1Hz to 100Khz, according to the datasheet.

LM331

There are several typical circuit applications using this V-F converter that can be found in the LM331 datasheet such as Precision Voltage to Frequency 100Khz Full Scale, Simple Frequency to Voltage Converter 10KHz Full-Scale, and Light Intensity to Frequency Converter.

Find Fairchild LM331 Voltage to Frequency Converter Datasheet here – http://www.datasheetcatalog.org/datasheet/fairchild/LM331.pdf

Yamaha TDM850 1996 Wiring Diagram and Electrical System

The Yamaha TDM850 is a Dual Sports or Adventure Sports motorcycle produced by Yamaha Motor Company of Japan, that first came out in 1991. The following wiring diagram and electrical system troubleshooting manual actually part of 1996 Yamaha TDM850 service manual. Herein you will find detail information regarding electrical system troubleshooting guideline and wiring diagram harness schematic of TDM850 which covers discussion on electrical components, switch inspection , ignition system circuit diagram and troubleshooting, electric starter system, starter motor, charging system, lighting system check, signal system wiring diagram, throttle position sensor self diagnosis.

The 1996 TDM850 electrical components consists of igniter unit, starting circuit cut-off relay, rectifier/regulator, main switch, thermo switch, thermo unit, flasher relay, starter relay, fuse box, battery, rear brake switch, sidestand switch, neutral switch, and ignition coil.

Find more info about 1996 Yamaha TDM850 Wiring Diagram and Electrical System here – http://www.carlsalter.com/aaman/Yamaha_TDM850_’96_Service_Manual.zip – free download PDF file

Lie detector circuitwith explanation

Here’s a simple lie detector that can be built in a few minutes, but can be incredibly useful when you want to know if someone is really telling you the truth. It is not as sophisticated as the ones the professionals use, but it works. It works by measuring skin resistance, which goes down when you lie.

Here are the details of the specific parts you will need

Part Total Qty. Description Substitutions

R1 1 33K 1/4W Resistor
R2 1 5K Pot
R3 1 1.5K 1/4W Resistor
C1 1 1uF 16V Electrolytic Capacitor
Q1 1 2N3565 NPN Transistor
M1 1 0-1 mA Analog Meter
MISC 1 Case, Wire, Electrodes (See Nots)

Notes
1. The electrodes can be alligator clips (although they can be painful), electrode pads (like the type they use in the hospital), or just wires and tape.

2. To use the circuit, attach the electrodes to the back of the subjects hand, about 1 inch apart. Then, adjust the meter for a reading of 0. Ask the questions. You know the subject is lying when the meter changes.

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

more at: electroniq.net/radio-frequency/fm-booster-schematic-circuit.html

Saturday, November 8, 2014

Dark Sensitive Power Switch Circuit Diagram Using LDR

DescriptionCircuit showing a Dark Sensitive Power Switch .Here we have used a ldr and a ordinary transistor for making this circuit
.Connect any 230 volt equipment at the load .You need a 9 volt power supply
Components Required

Resistor 10 k , 680 R

Transistor BC 548

Diode IN 4007

Relay LDR

Automatic Battery Charger

Normally, chargers available in the market do not have any sort of control except for a ro-tary switch that can select different tap-pings on a rheostat, to vary the charging current. This type of control is not adequate because of the irregular fluctuations in the mains supply, rendering the control ineffective. A simple circuit intended for automatic charging of lead-acid batteries is presented here. It is flexible enough to be used for large capacity inverter batteries. Only the rating of transformer and power transistor needs to be increased.

Circuit diagram :

Automatic Battery Charger Circuit Diagram

The circuit has been basically designed for a car battery (about 40 Ah rating), which could be used for lighting two 40W tube lights. The circuit includes Schmitt trigger relay driver,float charger,and battery voltage monitor sections. The Schmitt trigger is incorporated to avoid relay chattering. It is designed for a window of about 1V. During charging, when the battery voltage increases be-yond 13.64V, the relay cuts off and the float charging section continues to work. When battery voltage goes below 11.66V, the relay is turned on and direct (fast) charging of the battery takes place at around 3A. In the Schmitt trigger circuit, resistors R1 and R2 are used as a simple voltage divider (divide-by-2) to provide battery voltage sample to the inverting input terminal of IC1. The non-invert-ing input terminal of IC1 is used for reference input derived from the output of IC2 (7806), using the potentiometer arrangement of resistors R3 (18 kilo-ohm) and R4 (1 kilo-ohm).

LED1 is connected across relay to indicate fast charging mode. Diodes D3 and D6 in the common leads of IC2 and IC3 respectively provide added protecion to the regulators. The float charging section, comprising regulator 7812, transistors T3 and T4, and few other discrete components, becomes active when the battery volt-age goes above 13.64V (such that the relay RL1 is deenergised). In the energised state of the relay, the emitter and collector of transistor T4 remain shorted, and hence the float charger is ineffective and direct charging of battery takes place.

The reference terminal of regulator (IC3) is kept at 3.9V using LED2, LED3, and diode D6 in the common lead of IC3 to obtain the required regulated output (15.9V), in excess of its rated output, which is needed for proper operation of the circuit. This output voltage is fed to the base of transistor T3 (BC548), which along with transistor T4 (2N3055) forms a Darlington pair. You get 14.5V output at the emitter of transistor T4, but because of a drop in diode D7 you effectively get 13.8V at the positive terminal of the battery. When Schmitt trigger switches ‘on’ relay RL1, charging is at high current rate (boost mode). The fast charging path, starting from transformer X2, comprises diode D5, N/O contacts of relay RL1, and diode D7.

The circuit built around IC4 and IC5 is the voltage monitoring section that provides visual display of battery voltage level in bar graph like fashion. Regulator 7805 is used for generating reference voltage. Preset VR1 (20 kilo-ohm) can be used to adjust voltage levels as indicated in the circuit. Here also a pot meter arrangement using resistors R7, R8, and R9 is used as ‘divide by 3’ circuit to sample the battery voltage. When voltage is below 10V, the buzzer sounds to indicate that the safe dis-charge limit has been exceeded.

Increasing 78xx Voltage Regulator Current

Shown in the figure is an IC voltage regulator (also known as stabilizer), designed to increase its current output with the use of an outboard pass transistor. Voltage regulators are designed to produce positive inputs, such as 78xx series, and negative inputs, such as 79xx series. Using this circuit will help increase the current output from a 78xx series regulator. Alternatively, 79xx series can also be used with an NPN type of transistor.

Using a power transistor enables additional current to be loaded while sustaining a steady voltage. But keeping in mind for the limit of input voltage as it should be a few volts above the output voltage. Regulators like 7812, having a 12V output can be set to produce 20V output. Some 78xx series can surpass up to 36 volts input. Having a high power difference could lead to an overheat and would require sufficient heat sink. Without the heat sink, the transistor might collapse. Lower input could also cause failure due to the decrease in temperature. Power dissipation can be computed as the product of the voltage and the current P = V * I.
Source:www.zen22142.zen.co.uk

Friday, November 7, 2014

Solar Hot Water Panel Differential Pump Controller

This circuit optimises the circulation of heated water from solar hot water panels to a storage cylinder. It achieves this by controlling a 12V DC pump, which is switched on at a preset temperature differential of 8°C and off at about 4°C. This method of control has distinct advantages over some systems that run the pump until the differential approaches 0°C. In such systems, the pump typically runs whenever the sun shines. A small 10W solar panel charging a 12V SLA battery is sufficient to run the controller. Most commercial designs use 230VAC pumps, which of course don’t work when there is a power outage or there is no AC power at the site.

Operation:

Temperature sensors TS1 & TS2 are positioned to measure the highest and lowest water temperatures, with one at the panel outlet and the other at the base of the storage cylinder. The difference between the sensor outputs is amplified by op amp IC1d, which is configured for a voltage gain of about 47. As the sensors produce 10mV/°C, a difference of 8°C will produce about 3.76V at the op amp’s output (pin 14). The output from IC1d is fed into the non-inverting input (pin 10) of a second op amp stage (IC1c), which is wired as a voltage comparator. The op amp’s inverting input (pin 9) is tied to a reference voltage, which can be varied by trimpot VR3. When the voltage from IC1d exceeds the reference voltage, the output of the comparator (pin 8) swings towards the positive rail.

A 10MW resistor feeds a small portion of the output signal back to the non-inverting input, adding some hysteresis to the circuit to ensure positive switching action. A third op amp stage (IC1b) acts as a unity-gain buffer. When the comparator’s output goes high, the buffer stage switches the Mosfet (Q1) on, which in turn energises the pump motor. Mosfet Q1’s low drain-source on-state resistance means that in most cases, it won’t need to be mounted on a heatsink. The prototype uses a Davies Craig EBP 12V magnetic drive pump, which draws about 1A when running and is suitable for low-pressure hot water systems only (don’t use it for mains-pressure systems as it may burst!). For mains-pressure systems, the author suggests the SID 10 range of brass-body magnetic drive pumps from Ivan Labs USA.

Solar Hot Water Panel Differential Pump Controller Circuit Diagram

Setup:

Each LM335 temperature sensor and its associated trimpot is glued to a small copper strip using high-temperature epoxy. It is then waterproofed with silicon sealant and encapsulated in heatshrink tubing. Standard twin-core shielded microphone cable can be used for the connection to the circuit board. Before sealing the two units, adjust their trimpots to get 2.98V at 25°C [(ambient temperature x .01) + 2.73V] between the "+" and "-" terminals. When both have been adjusted, clamp them together and allow their temperatures to stabilise for a few minutes. Next, measure the output voltage from the differential amplifier (IC1d), which should be close to 0V. If not, tweak one of the pots until it is.

Separate the two and warm the panel sensor (TS1), monitoring the output of IC1d. You should see a marked increase in voltage, remembering that an 8°C difference between the sensors should give an output of about 3.76V. The pump switch-on point is set by VR3 and can be adjusted over a practical range of about 4-10°C differential (1.88-4.70V). Adjust VR3 to get about 3.8V on pin 9 of IC1c as a starting point. If set too low and the panels are located far from the cylinder, much of the heat will be lost in the copper connecting pipes. On the other hand, if set too high and the weather is mostly cloudy, then the pump will not switch on very often, as the panels will not get hot enough. For best results, use copper pipes for the panel plumbing and insulate them with tubes of closed-cell foam.

As the pipes cool down between pump operations, small diameter pipes of 15mm are more efficient than larger sizes as they contain less static water. In practice, the pump in the author’s setup switches on for about 30 seconds every 4-5 minutes. As the Davies pump shifts 13 litres/minute, it displaces the heated water from a single panel in about 14 seconds. There is a thermal lag in the sensor readings, so after the pump stops, the temperature difference will keep decreasing for 40 seconds or so as the panel sensor cools down and the cylinder sensor heats up.

Thursday, November 6, 2014

Simple 50W Hi Fi amplifier with TDA7294

The TDA7294 is a Hi-Fi amplifier and can give 100W RMS but with 10% distortion. Supplying 30 Volts you can have 50 Watts RMS with 1% distortion. Frequency range start at 16Hz and can reach 100KHz. Make sure you are using good heatsink. The chip supports mute function as well.

50W Hi-Fi amplifier Circuit Diagram
Simple

A symmetrical 30V power supply is all its need to power the unit.

resistor calculator

Resistor Calculator 1.0

Features of Resistor Calculator at a glance:

Calculating the color code of a resistor value.
Calculating the resistor value of a color code.
Displaying the closest resistor of the E series and Renard numbers.
Resistor calculation for LED circuits (single, in series, parallel).
Integrated help system.
Automatic program updates.
Multilingual (at the moment English and German).
Intuitive program interface.
Free e-mail support in case of problems or questions.
All updates for free.

>> Download Resistor Calculator source :http://www.ab-tools.com/English/software/resistorcalculator/

Battery powered Headphone Amplifier

Some lovers of High Fidelity headphone listening prefer the use of battery powered headphone amplifiers, not only for portable units but also for home "table" applications. This design is intended to fulfil their needs and its topology is derived from the Portable Headphone Amplifier featuring an NPN/PNP compound pair emitter follower output stage.

An improved output driving capability is gained by making this a push-pull Class-B arrangement. Output power can reach 100mW RMS into a 16 Ohm load at 6V supply with low standing and mean current consumption, allowing long battery duration. The single voltage gain stage allows the easy implementation of a shunt-feedback circuitry giving excellent frequency stability.

Battery-powered Headphone Amplifier Circuit Diagram:

Notes:

For a Stereo version of this circuit, all parts must be doubled except P1, SW1, J2 and B1.
Before setting quiescent current rotate the volume control P1 to the minimum, Trimmer R6 to maximum resistance and Trimmer R3 to about the middle of its travel.
Connect a suitable headphone set or, better, a 33 Ohm 1/2W resistor to the amplifier output.
Switch on the supply and measure the battery voltage with a Multimeter set to about 10Vdc fsd.
Connect the Multimeter across the positive end of C4 and the negative ground.
Rotate R3 in order to read on the Multimeter display exactly half of the battery voltage previously measured.
Switch off the supply, disconnect the Multimeter and reconnect it, set to measure about 10mA fsd, in series to the positive supply of the amplifier.
Switch on the supply and rotate R6 slowly until a reading of about 3mA is displayed.
Check again the voltage at the positive end of C4 and readjust R3 if necessary.
Wait about 15 minutes, watch if the current is varying and readjust if necessary.
Those lucky enough to reach an oscilloscope and a 1KHz sine wave generator, can drive the amplifier to the maximum output power and adjust R3 in order to obtain a symmetrical clipping of the sine wave displayed.

Technical data:
Output power (1KHz sinewave):
    16 Ohm: 100mW RMS
    32 Ohm: 60mW RMS
    64 Ohm: 35mW RMS
    100 Ohm: 22.5mW RMS
    300 Ohm: 8.5mW RMS
Sensitivity:
    160mV input for 1V RMS output into 32 Ohm load (31mW)
    200mV input for 1.27V RMS output into 32 Ohm load (50mW)
Frequency response @ 1V RMS:
    flat from 45Hz to 20KHz, -1dB @ 35Hz, -2dB @ 24Hz
Total harmonic distortion into 16 Ohm load @ 1KHz:
    1V RMS (62mW) 0.015% 1.27V RMS (onset of clipping, 100mW) 0.04%
Total harmonic distortion into 16 Ohm load @ 10KHz:
    1V RMS (62mW) 0.05% 1.27V RMS (onset of clipping, 100mW) 0.1%
Unconditionally stable on capacitive loads

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 :

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 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.

Inverter Overload Protector With Delayed Auto Rest

An overload condition in an inverter may permanently damage the power transistor array or burn off the transformer. Some of the domestic inverters sold in the market do not feature an overload shutdown facility, while those incorporating this feature come with a price tag.the circuit presented here is an overload detector which shuts down the inverter in an overload condition.

Inverter Overload Protector With Delayed Auto Rest Circuit diagram:

It hasthe following desirable features:

It shuts down the inverter and also provides audio-visual indication of the overload condition.
after shutdown, it automatically restarts the inverter with a delay of 6 seconds. thus, it saves the user from the inconvenience caused due to manually resetting the system or running around in darkness to reset the system at night.
It permanently shuts down the inverter and continues to give audio warning, in case there are more than three successive overloads. Under this condition, the system has to be manually reset.(Successive overload condition indicates that the inverter output is short-circuited or a heavy current is being drawn by the connected load.)

Inverter Overload Protector With Delayed Auto Rest

The circuit uses an ammeter (0-30a) as a transducer to detect overload condition. Such an am-meter is generally present in almost all inverters. this ammeter is connected between the negative supply of the battery and the inverter, as shown in Fig. 2. the voltage developed across this ammeter, due to the flow of current, is very small. It is amplified by IC2, which is wired as a differential amplifier having a gain of 100. IC3 (NE555) is connected as a Schmitt ‘trigger’, whose output goes low when the voltage at its pin 2 exceeds 3.3V. IC4 (again an NE555 timer) is configured as a monostable multivibrator with a pulsewidth of 6 seconds. IC5 (CD4017) is a CMOS counter which counts the three overload conditions, after which the sys-tem has to be reset manually, by pressing push-to-on switch S1. the circuit can be powered from the inverter battery. In standby condition, it consumes 8-10 ma of current and around 70 mA with relay (RL1), buzzer (PZ1), and LED1 energised.

Please note the following points carefully:

Points A and B at the input of IC2 should be connected to the corresponding points (A and B respectively) across the ammeter.
Points C and D on the relay terminals have to be connected in series with the already existing ‘on’/‘off’ switch leads of inverter as shown in Fig. 1. this means that one of the two leads terminated on the existing switch has to be cut and the cut ends have to be connected to the pole and N/O contacts respectively of relay RL1.
The ammeter should be connected in series with the negative terminal of the battery and inverter, as shown in Fig. 2.Move the wiper of preset VR1 to the extreme position which is grounded. Switch ‘on’ the inverter. For a 300W inverter, connect about 250-260W of load. Now adjust VR1 slowly, until the inverter just trips or shuts down. repeat the step if necessary. Use good-quality preset with dust cover (e.g. multiturn trimpot) for reliable operation.the circuit can be easily and success-fully installed with minimum modifications to the existing inverter. all the components used are cheap and readily avail-able. the whole circuit can be assembled on a general-purpose PCB. The cost of the whole circuit including relay, buzzer, and PCB does not exceed Rs 100.