Top Circuits Page 211
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This Hi Fi stereo preamplifier circuit is built with TDA1054 IC from SGS. TDA1054 is a 16-pin DIL package and integrates 2 separate preamp circuits. It is a low noise preamp with little or no problem in the building process. The first half of the circuit....
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This light dimmer control has active timing capacitor reset or AC line zero-crossing synchronization. The 13 additional components are garden variety and cost less than $2. Performance at the low end is exceptionally smooth and snap-free better even than the....
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The solar panels are operating at optimal parameters when they are at the perfect right angle to the sun. Unfortunately this is accomplished only if solar panels are rotated by the sun. This is the purpose of this diy solar tracker system or if you have an....
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This is a 1 watt fm amplifier with a good design that can be used to amplify a rf signal in the 88 108 MHz band. It is very sensitive if you use good rf power amplifier transistors, trimmers and coils. It has a power amplification factor of 9 to 12 dB (9 to....
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The G‚result of the lcd is not correct the thermometer does not show the room temperature but show the 414 degree then i need to know where is the problem is it in the hex file or in the sensor note (i connect vref+ on5v . and vref- on 0v) thanks for your....
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An Astable Multivibrator or a Free Running Multivibrator is the multivibrator which has no stable states. Its output oscillates continuously between its two unstable states without the aid of external triggering. The time period of each states are determined....
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Just like my previous circuit using LM358 this is also very cheap, also under 100 rupees. This is a circuit for controlling the street lights, garden lights, automatically. You don`t need to turn it on and turn it off again and again, just turn on the....
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The 230 V, 50 Hz is step downed using voltage transformer and current transformer is used to extract the waveforms of current. The output of the voltage transformer is proportional to the voltage across the load and output of current transformer is....
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A dancing light can be easily constructed using a 555 timer wired in astable mode. Please read the article Astable Multivibrator using 555 Timer before continuing. This circuit blinks two LEDsalternativelywith some delay and it can be easily modified to....
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A Digital Clock can be made easily by using PIC Microcontroller, DS1307 and a 16G—2 LCD. I have already posted about Interfacing DS1307 RTC with PIC Microcontroller. The DS1307 RTC can work either in 24-hour mode or 12-hour mode with AM/PM indicator. It....
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The difference between instantaneous frequency and central frequency of the carrier will be directly proportional to the instantaneous value of the amplitude of message signal. 555 Timer wired in Astable Mode can be used for generating Frequency Modulated....
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LCD (Liquid Crystal Display) is an electronic display which is commonly usednowadaysin applications such as calculators, laptops, tablets, mobile phones etc. 16G—2 character LCD module is a very basic module which is commonly used by electronic hobbyists and....
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16G—2 character lcd display is very basic module which is commonly used in electronics devices and projects. It can display 2 lines of 16 characters. Each character is displayed using 5G—7 or 5G—10 pixel matrix. Interfacing 16G—2 LCD with 8051 using Keil C....
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In some electronic applications we need to switch or control high voltages or high currents. In these cases we may useelectromagnetic or solid state relays. For example, it can be used to control home appliances using low power electronic circuits.....
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A servo motor uses servoG‚ mechanism, which is a closed loop mechanism that uses position feedback to control the precise angular position of the shaft. Stepper Motors, which is an open loop system can also be used for precise angular control. But Servo....
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LCD initializations in 8051 C programming words What is the logic behind the serial communication As in, how long should the SIG send out pulses and what should the delay be These statements are used to tell the compiler that a 16X2 LCD is connected to the....
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An IR Remote Control for controlling home appliances can be easily made using Decade Counter CD4017, 555 Timer and TSOP1738 infrared receiver. By using this circuit you can easily control your home appliances using your TV, DVD Player remote control or using....
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A simple and cheap Laser Based Security System, which costs below Rs. 100. It is a simple circuit using LM358 OP-AMP and LM555 Timer. This circuit is triggered when the Laser beam falls on the LDR interrupts, which sounds the buzzer connected to it. This can....
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Basically 8051 controller is Mask‚ programmable‚ means it will‚ programmed‚ at the time of manufacturing and will not‚ programmed‚ again, there is a derivative of 8051 microcontroller, 89c51‚ micro controller‚ which is‚ re-programmable. This device also have....
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For basic requirements we can use Square Wave Inverters which is very simple, low cost and easy to make. But for driving inductive loads pure sine wave inverters are preferred. Here we are dealing with a Simple Low Power Square Wave Inverter using CD4047. It....
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Matrix Keypad is a very useful and userfriendly when we want to design certain applications like Calculator, Telephone etc. MatrixKeypad is made by arranging push button switches in rows and columns. Just imagine, if you want to interface a 4*4 (16 keys)....
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It initializes a particular port for working with keypad. A global variable keypad Port must be defined before using this function. Port need to be initialized before calling this function. This function reads key when a key is pressed and it returnsnumber....
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As its name indicates it has one stable state and it switches to unstable state for a predetermined time period T when it istriggered. The time period T is determined by the RC time constant in the circuit. Monostable mode of 555 Timer is commonly used for....
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For making a power supply designing‚ of each and every component is essential. ‚Here I`m going to discuss the designing of ‚regulated 5V Power Supply. NOTE : Any transformer which supplies secondary peak voltage‚ up to35V can be used but as the voltage....
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The 555 IC is wiredin monostable mode of operation. Please read the article Monostable Multivibrator using 555 Timer for more details. In this mode the output is LOW (0V) when there is no triggering, when it istriggeredvia 2nd pin the output goes HIGH (Vcc)....
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In Capacitor Power Supplies we use a Voltage Dropping Capacitor in series with the phase line. An ordinary capacitor should not be used in these applications because Mains Spikes may create holes in dielectric of ordinary capacitors and the capacitor will....
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Voltmeter and Ammeter can be easily made using PIC Microcontroller having ADC (Analog to Digital Converter). I am using PIC16F877A and the result is displayed on an LCD Display. PIC16F877A is enough if you do this project only for testing purposes. I suggest....
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Using the principles of a horizontal steam engine I constructed a model in which the steam cylinder is replaced by an electromagnet with a moving core. The construction details of the model are of little importance, as the photos give all the information you....
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The control of electric motors is something which interests nearly everyone involved with Meccano model building. Every model has its own motor requirements with regard to the space available, the power of the motor, its speed, whether it must stop and start....
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The prototype for this model is one of a `DSG` class of 24 locomotives built in 1981 by Toshiba for the New Zealand Railways. These locomotives weigh 56 tonnes and have two diesel engines, providing a total of 750kW. In more recent years they have been....
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This Frequency Counter is suitable to display the frequency of a frequency generator with an analog setting. It is a very simple counter and can be used as a module in a box with a frequency generator. It does what it says, it measures frequencies up to 2....
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A simple pulse generator with a variable duty cycle and frequency is often useful in the lab to trigger or test other devices, e. g a servo with a frequency of 50 Hz and pulses between 1 and 2 ms. This is where the project started but for reasons we see....
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The time can be set with a potentiometer between 1 minute and 1023 minutes, about 17 hours. A pushbutton starts the time, turns on a relais and the timer will turn off the relais when the time is elapsed. It can be switched to seconds for a shorter time....
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This is a very practical device and I built it so that it is a module to my Dual Channel IR Remote Control. Because of that I ended up with a definite overkill of what is supposed to be a simple switch with a timer when I open/close my door. Anyway, it is....
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It is based on NE555 as simple noise-maker whose output is fed to a single transistor oscillator. The oscillator is designed to operate between 800MHz and 2GHz which happens to be the frequency span used for GSM phones. The frequency of operation is set with....
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Take photos in 360 degrees. That kind of photo is actually an animation that consists of several photos of the same product but from different angles. It means that we need a device that can be controllable and that could take pictures on even intervals. As....
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This is a very-very high power Inverter circuit which will give you very high AC power output 3000W. This inverter will convert 12 Volt DC Battery voltage into a square wave voltage of 50 cycles per second and duty cycle of 25% ..
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This bulletin outlines applications, design features, equipment arrangement, and space planning, for the type 230 controllers. These controllers are for the control and protection of induction motors or transformers on 2300-4160-volt systems. Each type 230....
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This PSU has been especially designed for current-hungry ham radio transceivers. It delivers safely around 20Amps at 13. 8V. For lower currents, a separate current limiting output, capable of 15ma up to a total of 20A has been added. Let us see what we have....
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This is a small but quite powerful FM transmitter having three RF stages incorporating an audio preamplifier for better modulation. t has an output power of 4 Watts and works off 12-18 VDC which makes it easily portable. It is the ideal project for the....
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The transmitter circuit described here has an extra RF power amplifier stage, after the oscillator stage, to raise the power output to 200-250 milliwatts. With a good matching 50-ohm ground plane antenna or multi-element Yagi antenna, this transmitter can....
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A teleremote circuit which enables switching on` and off` of appliances through telephone lines. It can be used to switch appliances from any distance, overcoming the limited range of infrared and radio remote controls. The circuit described here can be used....
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The circuit would automatically light a bulb on arrival of a telephone ring and simultaneously mute the music system/TV audio for the duration the telephone handset is off-hook. Lighting of the bulb would not only indicate an incoming call but also help in....
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A simple calculator, in conjunction with a COB (chip-on-board) from an analogue quartz clock, is used to make a telephone call meter. The calculator enables conversion of STD/ISD calls to local call equivalents and always displays current local call-meter....
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an easy to build, but nevertheless very accurate and useful digital voltmeter. It has been designed as a panel meter and can be used in DC power supplies or anywhere else it is necessary to have an accurate indication of the voltage present. The circuit....
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To design and build a wireless transmitter that works over the FM frequency and allows the transfer of a video/audio signal over a certain distance to an FM tuner. In this fast-paced world, there is little time for inconveniences and a greater need for....
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The circuit is a broad band amplifier which will take the video signals from your VCR and will amplify them sufficiently to drive up to 3 monitors, TV sets (provided that they can accept direct video signals), or other VCR ½s for recording from one video to....
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Video signals can be difficult to display on an oscilloscope. Normal trigger circuits in most oscilloscopes have trouble getting a stable trigger from the combined vertical and horizontal sync signals, color burst, and picture signal in a composite video....
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This circuit allows you to superimpose a title and/or the time and sate on an incoming video signal - very useful when editing video tapes. It`s also a good introduction to video signals and processing. The text that follows is from David`s article: With the....
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This is vWalker v1. The "v" standing for V, as in five. It is a five motor walker that goes towards light and avoids obstacles. The goal was to create a walker that could navigate over rough complex terrain while seeking out the brightest source of light.....
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The Atmel AVR series are very good microcontrollers with quite a rich instruction set, rich enough that lots of folks have good compilers for them so we don`t have to learn their assembler. A very rich compiler available is the BASCOM/AVR compiler from MCS....
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ICs have largely replaced circuits such as this, this circuit still finds use where the flexibility of a discrete device design is desirabe. Parts are easy to obtain and the problem of IC obsolescense is eliminated. The TIP31A can be heatsinked to a small....
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This simple tone control can be used in may audio applications. It can be added to amplifers, used as a stand alone control module, or even built into new and exciting instruments. It`s one IC construction makes it a very compact circuit, as only a few....
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This circuit utilising a 555 timer IC can be used as an alarm system to prevent the theft of your luggage, burglars breaking into your house etc. The alarms goes ON when a thin wire, usually as thin as a hair is broken. The circuit is straightforward. It....
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The circuit presented here is a simple audio/video transmitter with a range of 3 to 5 metres. The A/V signal source for the circuit may be a VCR, a satellite receiver or a video game etc. A mixer which also operates as an oscillator at VHF (H) channel 5 TV....
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This simple micro-control circuit controls a servo motor according to a 3-state switch. A servo motor acts as an actuator in 3 position. It has 3 wires, one for VCC, one for Ground and another one for position control. The last signal is a single pulse with....
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This circuit is designed to amplify the input from a telescopic whip antenna. The preamplifier is designed to cover the medium waveband from about 550Khz to 1650Khz. The tuning voltage required is 1 to 12 volts and can be obtained from a 10k potentiometer....
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The original data sheet for the MK414 states a maximum working frequency is around 4 MHz. SW transmissions are so powerful that this receiver will work well with signals up to about 6 or 7 MHz. The 10k resistor controls the operating voltage for the IC which....
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This small transmitter uses a hartley type oscillator. Normally the capacitor in the tank circuit would connect at the base of the transistor, but at VHF the base emitter capacitance of the transistor acts as a short circuit, so in effect, it still is. The....
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The circuit uses two 2N3819 FET`s in cascode configuration. The lower FET operates in common source mode, while the upper FET, operates in common gate, realising full high frequency gain. The bottom FET is tunable allowing a peak for a particular station.....
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Contrary to what some radio experimenters think, a bipolar regenerative design can be made to work efficiently. The major concern is the low input impedance of the detector-amplifier bipolar stage. Nevertheless, it can be easily compensated with positive....
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This circuit provides a visual 9 second delay using a 7 segment digital readout LED. When the switch is closed, the CD4010 up/down counter is preset to 9 and the 555 timer is disabled with the output held high. When the switch is opened, the timer produces....
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In the circuit below, 60 individual LEDs are used to indicate the minutes of a clock and 12 LEDs indicate hours. The power supply and time base circuitry is the same as described in the 28 LED clock circuit above. The minutes section of the clock is....
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The circuit below illustrates using a 10x10 matrix to sequence up to 100 LEDs with just three ICs and 20 transistors. The two 4017 decade counters control the 10 rows and 10 columns so that one LED is selected depending on the output of the decade counters.....
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This circuit is similar to the "Fading Red Eyes" circuit (in the LED section) used to fade a pair of red LEDs. In this version, the lamps are faded by varying the duty cycle so that higher power incandescent lamps can be used without much power loss. The....
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This simple design has very low noise, close to the theoretical minimum, high hum rejection and variable gain with a single rotary pot. It is similar to that used in many professional grade mixing desks and can form the basis of a no compromise recording....
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The lower FET operates in common source mode, while the upper FET, operates in common gate, realising full high frequency gain. The bottom FET is tunable allowing a peak for a particular station. Coil details follow:..
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The first IC (left) is wired to work around 1Hz. The 47uF capacitor is charged and discharged periodically and the voltage across it gradually increases and decreases periodically...