Top Circuits Page 214
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Using a single op-amp this easy to make equalizer offers three ranges, low frequency, mid frequency, and high. With component values shown there is approximately +/-20dB of boost or cut at frequencies of 50Hz, 1kHz and 10kHz. Supply voltage may be anything....
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The first BC109C transistor (left hand side) is acting as a buffer. It provides the circuit with a high input impedance, around 250k has a voltage gain of slightly less than unity. As the Baxendall tone control circuit is a passive design, all audio....
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This circuit consists of two identical intercom units. Each unit contains a power supply, microphone preamplifier, audio amplifier and a Push To Talk (PTT) relay circuit. Only 2 wires are required to connect the units together. Due to the low output....
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This circuit uses a couple of Op-amps to produce an interesting sound effect. The left hand CA741 is wired as a standard astable and produces the timing pulses, controlled by C1, R2 and VR1. The output is fed via C2 to the second op-amp and is also direct....
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A power supply project without using a power supply. This can save the expense of buying a transformer, but presents potentially lethal voltages at the output terminals. Under no circumstances should a beginner attempt to build such a project. Electric Shock....
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The 555 circuit can be re-triggered if the input is held low longer than the output pulse. To prevent this happening, I have included a further timing circuit comprised of the 1Meg resistor and 47n capacitor. Normally, the 47n capacitor is discharged via the....
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This circuit is designed to operate an electrical door-release mechanism - but it will have other applications. Enter the four-digit code of your choice - and the relay will energize for the period of time set by C4 & R4. Use the relay contacts to power the....
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The first positive pulse from a classic 555-based oscillator is always 1. 6 times longer than the following pulses. The difference is caused by the fact that only during the first cycle C2 starts charging up from 0 V. This is generally not a problem, but....
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This index is arranged alphabetically on each word (except prepositions). For example, the "Frost Alarm" will be indexed under "A" and also "F". To quickly find a circuit use the top index or try your browsers search function. In Firefox, Konqueror, Opera....
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Although only low power this circuit may be tuned to operate over the range 87-108MHz with a range of 20 or 30 metres. I have used a pair of BC548 transistors in this circuit. Although not strictly RF transistors, they still give good results. I have used an....
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This new loop antenna by Graham Maynard is his best design yet and I am proud to be the first to present his work. It uses one, six foot square, six turn loop, and is aperiodic in nature, covering the frequency range 50KHz - 5000KHz. The loop is of a size....
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This is a compact three transistor, regenerative receiver with fixed feedback. It is similar in principle to the ZN414 radio IC which is now replaced by the MK484. The design is simple and sensitivity and selectivity of the receiver are good. All general....
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All ATL-3 loop windings are centre tapped and balanced w. r. t. their amplifier/receiver chassis ground, and therefore electric field interference pick up tends to self cancel. Magnetic noise fields, e. g. televisions and the electric meter box, or....
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A simple passive (no power required) circuit to match an antenna to a radio receiver. This will be a useful addition to the short wave listener, but in addition a medium wave coil is almost used to tune the medium wave band. An aerial tuning unit (A. T. U. )....
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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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This simple transmitter operates from a 9V battery as shown above. I personally built this for a purpose. This is how it happened:- "members of my singing group find it difficult to handle a FM mic in Church. The choir sings in acapella form and the....
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This is a wide band signal strength meter circuit which responds to small changes in RF energy, designed to be used for the VHF spectrum and will respond to AM or FM modulation or just a plain carrier wave. This circuit measures radio field strength by....
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The multimeter should be set to the lowest dc volts range for maximum sensitivity. This is normally 200mV DC for most meters. The circuit works well at VHF (around 100MHz) and was quite pleased with the results. L1 was 7 turns on a quarter inch former with....
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The problem with amplifying weak radio signals is that you also amplify the noise. What you can receive depends on how much background noise is present, whether it be man made interference or static. In this design the RF signal is first met by a resistive....
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The circuit requires an RF input which can be from a longwire or a loop antenna. The Preamplifier has a range from 550kHz (Medium Wave) up to 30 MHz in the SW band. The input Switch S1, applies voltage to a set of relays which switch in the appropriate....
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Electronic devices love accuracy. If you give them the same task twice, you will get the same resault. But sometimes you want some random result. This can be used in games. You can create your own lottery game. We will help you to do that kind of game with....
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This page describes how I have modified my SkyWatcher dual axis EQ5/EQ4 motor controller to allow autoguiding through the parallel port from a PC. The modification allows the RA+, RA-, Dec+ and Dec- buttons to be activated from the PC via the parallel port....
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Because the Neon has inboard mounted turn signals, they are not visible from the side. Typically a manufacturer will mount a second light that is visible on the side or make the side markers blink, as they did on the 9x Neons. However on the North American....
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A light dimmer that uses TRIAC & DIAC. Controls the brightness of light bulbs. Based on the standard dimmer circuit. A few additional parts were added to eliminate flickering at low light level. Works better then commercial units...
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An oscillator is an amplifier with a feedback loop from output to input. Barkhausen criteria states that for oscillation to occur the product of the gains around a loop must be equal to or greater than unity and that the sum of the phase shifts around the....
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ET6201 is 1/ 7~ 1/ 8duty cycle of the LED display control drive circuit. By 11, the 6root root segment output gate output, 1root segment / gate output, a 1display memory, the control circuit, key scanning circuit composed of a high reliability of the chip....
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The encoder strip should be laser-printed on sticky label material (ink-jet might work, I haven`t tried it). It is then cut out and wrapped around the barrel of the second drive gear. I used bright white sticky address labels Avery "WeatherProof White....
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Connect the Negative side of the positive supply to the Positive side of the negative supply to create a +/-15vdc. This junction is the ground for the transducer to ensure a balanced voltage. 9) Continue the experiment by switching the power off, changing....
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This project uses the similar technique to these products, however it can write a continuous stream of text using a high speed rotor and a strip of LEDs. The word WhirlyGig is derived from the word whirl meaning to spin, and the acronym GIG which stands for....
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Wondered how to control the MR2 Power steering pump so that it is not a noisy power hog because it ’s always on full throttle. Designing some sort of motor controller or using a small off-the-shelf controller would not work for me. One, I ’m not that great....
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VLQC is a quenching circuit designed in our laboratories to perfectly suit the constraints of an array, i. e. high compactness, cross-talk avoidance and low afterpulsing. In VLQC a single transistor performs the sensing, quenching and reset tasks drastically....
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Here we show you how to hack a TV-B-Gone into the case of a vintage television remote control, such that the original on/off button instead activates the TV-B-Gone. We also modify the power supply so that it runs off of a regular 9 V battery, instead of a....
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Drive a blue or white LED from a low voltage. Normally, if you want to light up a blue or white LED you need to provide it with 3 3. 5 V, like from a 3 V lithium coin cell. But a 1. 5 V battery like a AA cell simply will not work. But using the Joule Thief,....
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Here`s an inexpensive electronic circuit that you can build to put in your Jack-o`lantern. It provides power to drive a few LEDs at night, and automatically turns them off during the daytime. It`s a simple and automatic dark-detecting circuit that you can....
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Tennis for Two presented a tennis court shown from the side on an oscilloscope screen, where handheld controllers allowed the two players to toss the ball to each other. Each controller had two controls: a button and a knob. With the button, you could hit....
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The line-in pin is clearly visible in the pinout of iPod connector shown on the iPod wiki. From then they came a long way through making their first hand soldered mic to now selling neat small mics on their site. They have got their own SIP VoIP servers....
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The Panasonic transducers are no longer available, but the design is still interesting as an example. J1 is the connection to the RCX. D1 - D4 form a bridge rectifier to obtain local power from the RCX which is stored on C7 and regulated to 5V by U1, a low....
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This analog sequencer was designed with the idea of cooperative play in mind. It can be used as a standalone instrument, or linked together with other sequencers running on the same clock speed. Mark Kleback and I were working separately working on....
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More examples to connect your transceivers to the computer for SIMPLEX software operations are described in the pc_tx. bmp file that is included in the simplex. zip file...
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This article describes a 2 meter amplifier capable of running 25-30 watts output. More than 35 amplifiers have been procured at a cost of less than $50 each in these quantities. Photo A shows the final version of the circuit board; the completed amplifier is....
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The Fuel and Temperature gauges as used in the 1960 - 1965 Ford Falcon are very basic instruments whose operating principles seem to have gotten lost in this modern day era of digital electronics. In order to properly troubleshoot the circuits you will need....
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Thomas Edison developed the incandescent light bulb, which operated from a 110 volt DC source. The primary drawback to DC power was that it could only be distributed over short distances without having to be regenerated. In the early 1900s when Nicoli Tesla....
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The Mark III conductivity-temperature-depth (CTD) profiler has been the mainstay of modern physical oceanographic research1. The MKIIIB CTD provides high quality oceanographic data when used by skilled personnel and are frequently re-calibrated. The design....
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The robot was controlled with a Motorola 68HC11 on a special MC11 input/output board furnished by the Stanford Smart Product Design Lab (SPDL). The SPDL also furninshed motor controller boards, each consisting of a DS3658 stepper controller, a SN754410....
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The Slave Flash Trigger is switched on/off by pressing the push button. When switched on, one to three flickers of the indicator lamp signalizes the programmed mode. One flicker determines that the flash will be fired at each flash. Two flickers indicate....
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Digital circuits are circuits dealing with signals restricted to the extreme limits of zero and some full amount. This stands in contrast to analog circuits, in which signals are free to vary continuously between the limits imposed by power supply voltage....
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Thyristors are a class of semiconductor components exhibiting hysteresis, that property whereby a system fails to return to its original state after some cause of state change has been removed. A very simple example of hysteresis is the mechanical action of....
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This project combines several features in one compact unit. The fundamental driver consists of a NE 555 square wave generator. During development, consideration and a certain amount of experimentation was given to the construction of a square wave unit using....
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This circuit doesn`t work as well as it could. I made it when I had a lesser understanding of circuit design. I`ll probably make a new and improved schematic and post later on, one that has a better design. Thanks for stopping by! Note: The schematic here....
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The basic charging circuit produces in excess of 500V+, depending on the inductor used, leakage of various components, etcetera. The current output is limited by a 10Mohm resistor, which keeps short-circuit current under ~60uA. Thus this is a relatively safe....
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To convert the MaCom 10GHz "White Box" (or "Whitebox" for the search engines) unit for ham radio use. Since we`re following in the path of others who`ve already modified these units, there isn`t much new here in the way of modification instructions, but I`ve....
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Make Z3801A GPS-disciplined oscillators more useful by making 1 PPS and additional 10MHz signals available on the rear panel, and providing a 1 PPS signal on the DCD line of the serial connector so the unit could serve as a reference clock for an NTP server.....
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Experimenting with `gainclone` amplifiers. Gainclone amplifiers use opamps instead of the tubes and transistors that can be found in most amplifiers. I now present the second reincarnation of the Chill-amp concept. My interest in trying something with opamps....
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This site is primarily for me to collect together things that I find useful that I don`t want to forget but occasionally I may put together some pages that others may find interesting. Please have a browse and see what you can find. I tried to make the....
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This is a good Electrical & Electronics mini project report on "Remote Controlled Fan Regulator" and submitted in accordance with the curriculum requirements for sixth semester of the degree course in Bachelor of Technology in the branch of Electrical and....
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This is a good project on GSM Based Home Automation and submitted in partial fulfillment of the requirements for the degree of bachelor of technology in Electronics and Communication engineering. The goal of the project is to develop a system, which uses....
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This is a good Electronics & communication project on GSM Based Voting Machine System which uses AT commands to sens SMS through Microcontroller. The project has 2 modes viz. Normal mode and Security mode. In normal mode an authorized person of a local area....
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This is a good Electrical project report on Infrared Remote Control On/Off Switch and was Submitted in partial fulfillment of the requirements for the award of the degree of Bachelor of Engineering in Electrical Engineering and is used to switch on/off the....
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This is a vocational training report on Ultrasonic Proximity Detector undertaken under at Bharat Heavy Electrical Limited (BHEL)in partial fulfillment of the requirement for the Bachelor in Electrical engineering. The report covers topics like Making Printed....
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This is a good Electronic project report on Speed Control of DC Motor using Microcontroller by using PWM. In this system, a micro controller is interfaced with a LCD, Keypad and DC motor driver. The Micro controller is used for controlling the DC motor by....
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This project Microcontroller based college automation system , aims to eliminate this problem especially in case of colleges and schools. In this project conventional notice board is replace by a well automated device. The circuit enables the user to hear....
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The goal of the project is to develop a system, which uses Mobile technology that keeps control of the various units of the home appliances, which executes with respect to the signal sent by the mobile. For utilization of appliances the new concept has been....
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Objective of this project are to Design a circuit of an electronic infrared communication system, develop new ideas to implement this circuit purposely, to study the circuitry and different types of components & DTMF generator, DTMF decoder, op-amp and....
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The aim of developing this project is to control the speed of DC motor. The main advantage in using a DC motor is that the Speed-Torque relationship can be varied to almost any useful form. To achieve the speed control an electronic technique called Pulse....
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This circuit might also be of interest to people making pre-amps for electret and externally polarized condenser microphones which have no internal FET. (If a single FET`s noise is the limiting factor, perhaps two or four could be run in parallel. ) Some....
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Default setting for the UART is 9600 baud, 1 start bit, 1 stop bit, no parity. You can configure this paramter by placing the file "CONFIG. TXT" to the USB thumb drive. Currently only the baudrate can be configured. Example: Once the device is connected and....
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For this test you will need an analog (non-digital) voltmeter. Do NOT remove the distributor connector. Using small paper clips, insert them into the backside of the distributor wire harness connector to make contact with the terminals. Do NOT damage the....
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The schematic is in PDF, and cannot be send to you by this site. Check this site. It has some schematics. Check whether the schematic you need is there. Pull up older posts there. I have a WS-55807 that will not power up. When the power button is pressed I....
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Circuit for Grundig 5441 tv. If you have any problem regarding this issue come back with more information about the problem, we will glad to assist you By entering the Fixya site you declare that you have read and agreed to its Terms. You may NOT copy or....
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Fixing a television (as it was given to me). I am hoping to find at least which area on the schematic is related to the pincushion circuit, as this seems to be the only problem with the tv. The first thing I checked was for dry joints or poor soldering. I....
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The voltage regulator built onto the Arduino Uno is a linear-type regulator and is horribly inefficient. If you are running the ATmega238 at 5V using a 9 V battery, approximately half of the battery`s energy will be dissipated as heat by the regulator. This....