Top Circuits Page 129
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Here`s a small FM transmitter ciruit for your desktop or laptop to enjoy the movie and music from a distance. This FM transmitter, which is powered by USB, recovers output on your computer or your MP3 player to the relay on the tape FM (frequency 108 MHz).....
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Each step will result in a self functional unit. In the end of this journey, you will be able to link the steps together into a very powerful FM transmitter. This part will explain the main controlling unit for the FM transmitter. This part is very important....
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In this file is a schematic for a simple wiretap & instructions for hooking up a small tape recorder control relay to the phone line. First, I will discuss taps a little. There are many different types of taps. There are transmitters, wired taps, and....
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Since this is a DC circuit, how and where do the + vs. the - wires physically get connected to the circuit Where exactly do I connect all the grounds to I understand all the places where the schematic calls for a connection to the power source. I`m just....
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Design a Colpitts Oscillator in a common collector configuration using a single BJT. Provide base current to get the transistor operating properly, and you can do this using a potential divider (between Vcc and gnd): use resistor values as high as possible....
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The circuit is two separate 3023 optoisolators driving two separate triacs, each one powering a large 3-phase contactor. One contactor is engaging fine. The other one is rattling badly because it isn`t getting full power to pull in. The top photo shows trace....
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The intended result is that the relay oscillates and the LEDs flash when the button is pressed, however when I press the button the leftmost LED lights constantly and nothing else happens. I get voltage across the left LED, the resistor and the capacitor,....
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nokia 5130 keypad jumper just follow the diagram.. tested just now.. after doing the jumper.. all keypads working well ....
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I want the final package to be as invisible as possible, and without any wires / adapters / etc. Obviously that requires me to run this project from a small battery. To preserve power, I`m thinking about putting the ATMega (eventually probably the ATTiny)....
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I`m not planning to remove the links to stable versions right now. Want to do it at the end of this month to exclude for sure any possible issues with ....
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The heart of the switch controller is an Arduino Nano micro-controller - this is going to be the interface between the dashboard switches, wireless steering wheel buttons and the car`s lighting, indicators, windscreen wipers and DigiDash2 GPS stopwatch. This....
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We have a Subaru Brumby which has been with us for some time. Our mechanic says that the engine is ....
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Hi all,So I will be running with a high voltage pack in both the eCRX and the electric race bike. Both ....
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I have a 05 wildfire 250 qac i think thats wat it is. mine wont start either. When i try to start it it sounds like the gears from the starter to the other gears are just spinning. I got mad and flippied it the one day and ever since theen its been like....
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While driving car the gauges goes off and the car stall immediately. Car will not start until gauges come back on. While gauges are off the car starter will turn over the motor, but will not start. First time about 5-10 minutes before gauges are back on and....
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I have been looking for information on how to install factory HIDs into an Evo that did not come with HID or fog lights to no avail. Here is something ....
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I need some information about a circuito to manage ma Remote COax Ameritron RCS-10, I can`t find on google some information about a diagram....
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Works but the windows go slow, you hook 12 volts directly to the motors and they zip up fine. I saw a post from several years ago where someone was trying to use the common 5 pin ice cube relay. never saw anything that said it worked. Anybody know the power....
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Greetings to all. This is my first post, yet I am no stranger. Please accept my thanks for the many postings all of you have made: you have taught me....
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I am currently following the two guides here: Original Guide Hackerspace/Coding4fun Thundergod Guide using netduino mini This is the basic circuit. But I would l ....
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I was sitting around trying to decide how to wire my fog lights up. I`ve seen people wire them directly off the low beam or....
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I have several Hall Effect sensors and would like to use them with my BS2. One application would be to count wheel turns. I have done a search of the internet but can not find a schematic for connecting it to a BS2. Can anyone help me out with a schematic? I....
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I was inspired by the excellent work done by others on these boards using DMX sequencing and various parallax products to interface with them. I decided to take my crack at it using the propeller only with a slightly different spin, pun intended. I decided....
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Develop a cheap high-current circuit and still use PWM. Specifically, did I get the flyback diodes right I placed the high-speed Schotkky clamping diodes in the circuit to protect the MOSFET from the CEMF generated by the motor as the power is switched....
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Hi Parallax people, just joined the forum. I`m trying to control a CPU fan with a relay triggered by a stretch sensor. I have my circuit set up like this. Right now the stretch sensor isn`t attached, however when I power the circuit it just pulses like in....
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Well since I learn fastest by doing (not exactly unique I guess) time to start my next trick. Adapting one of the many curve tracer schematics, probably Metzger`s circuit from the early `70s with modifications to an ADC capture system and output to a 320*256....
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Sid, I put together two working examples, one using a PNP and NPN transistor, and one using two MOSFETs. Both work fine, but as expected the MOSFET circuit consumes much less current (0.1 mA vs. 4.5 mA). Comments, suggestions, and bug reports gratefully....
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I recently created a ""Steady Hands Game"" - it started off as·eaching the need to have a game for a cub-scout event. However after prototyping the game (on the homework board), I created a more premanent version of this game that can be used for teaching.....
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I want/need better headlights. I`ve been trying to study up on this - including the on-going forum discussions. But, I think I need some basic info....
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The "crossed-flags" topology of a monostable multivibrator. Also, this particular board happened to be a 912 tach, so R5, which determines the discharge rate of C2,would be different for a 911. 912`s have a 50% duty cycle (four cylinders, 45 degrees of dwell....
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I have 6 injectors from a Suzuki bike with unknown flow rates. Can I flow them myself to see what I have?....
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Originally Posted by CliffBrown Sal Thanks for the reply. If the plugs could be purchased and the signals fed to the PC with the software you`re using ....
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I am trying to get to the bottom of some low RPM problems and wanted to get some expert opinions before i start cutting wire looms apart to trace a....
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Getting ready to put Adrian`s Pololu stepper driver circuit together and have run into a question. He mentions that if you are using 5v from the Arduino Mega, to leave out the 78L05. Great! I am thrilled to only have the wrong symbol for ground. I have just....
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Just wondering if there was a simple way to bypass the tone contols in the pas preamp. I believe there is a feedback circuit involved, so wasn`t sure ....
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MMC Programmer - Memory Card Unlocker, Portable Devices, Handhelds, palmtops, cellphones, PDAs, pocket organizers, and all those other devices that make computing part of your lifestyle ....
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Transmitting Voice Wirelessly Using Laser, Tips & Tweaks, Windows tips and tweaks to enrich your computer operating system experience ....
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I am interested in creating an interactive LED gameboard of some kind (or even a sort of "Stargate" DHD-type sci-fi prop!), where each square or tile is lit up from below by either a single white LED or an RGB combo. It always occurred to me that I`d love it....
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The H-bridge: The H-bridge is a commonly known, and commonly used way to drive a brushed DC motor. It allows for simple forward/reverse drive, ....
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from the mk5 subforum, but thought it better to start a new one given that it relates specifically to a mk6 although probably 90% the same. Plan is to retrofit park assist to a mk6 without PDC. Needed: New park module (1T0919475H) addional wiring harness for....
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Ok. So I`ve bought and sold 10 MK3 Jettas and 1 MK3 Golf. Never posted on a forum before. I paid $400 for a 1994 GTI, in order to fix it and sell it, so theres that. The car ran 2 years ago, when my friend was driving it home from 2.5 hours away, it died on....
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Hi lads, I thought I`d start a thread on the diagrams I`m making. This first set is for DOSD. After a potential problem was discovered recently these new diagrams will enable you to wire up the DOSD perfectly safely avoiding the potential problem. Click on....
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I finally got all of the materials I needed in to work on my arduino powered Diversity controller. The plan is to support 2 inputs (though the hardware can support up to 4 inputs), and 4 amplified outputs. The diversity will use RSSI to compare feeds and I....
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If you can`t see any characters displayed on the LCD (and you`ve checked that the hardware and software are working) turn the LCD Contrast pot until you can see the characters. To load an 8 bit character or LCD command into the 74HC164 shift register, the....
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VU LED indicator is simpler and smaller than their analog, and very common in audio equipment. This version is based on National Semiconductor IC, and using the logarithmic version. Each LED operates with a 3dB difference from before, and the jumper is....
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Stop watch is made with a digital timer IC LM555 and IC MM74C926 4 digit counter with multiplexed 7-segment LED. MM74C926 consists of4 digit counter, an internal output latch, NPN output for controlling the source of common cathode, 7-segment display and an....
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It can be adjusted to give the desired speed for the display. The output of the 555 is directly connected to the input of a CD 4017. The input of the counter is called the CLOCK line (555). The 10 outputs become active, one at a time, on the rising edge of....
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Decade counter circuit is a electronic circuit to perform a sequence of numerical calculations either forward or backward calculation. What is meant by forward calculation is where the circuit will count ranging from small numbers to larger numbers. While....
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This circuit can be used for an assist in parking the car near the garage wall backing up Pls. LED D7 illuminates Pls bumper-wall distance is about 20 cm. , D7 + D6 illuminate at about 10 cm. and D7 + D6 + D5 at about 6 cm. In this manner you are alerted Pls....
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To connect two computers or connecting two HUB / switch with UTP cable, can use a crossover cable. If you connect computers to the HUB / switch, use straight cables. Straight cable is a term for a cable that uses the same standards on both ends of its wires,....
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Make a USB to Serial Converter own with ATmega8 microcontroller. In this ATmega8 will be given free firmware source code and can be downloaded at the bottom. Because the ATmega8 there is no facility for communication with the USB, then inevitably the data....
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An electronic recitification circuit. The use of large, heavy and expensive electrolytic capacitors is avoided, being replaced by an active transistor in this gyrator circuit. To avoid excess ripple output on a power supply feeding a heavy load, usually a....
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The Hartley Oscillator is characterised by an LC circuit in its collector. The base of the transistor is held steady and a small amount of signal is taken from a tapping on the inductor and fed to the emitter to keep the transistor in oscillation...
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The simplest method of detecting metal is by beat frequency oscillator. The circuit basically consists of two balanced oscillator. One acts as the detector element, the other provides the reference signal. This oscillator frequency reference is set to fix....
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Connect the two sections of the variable capacitor (C3) in series to linearize the tuning somewhat. That is, use the connections on either end of C3 and don`t use the middle lead. The gain is just enough to drive an earphone. If you live too far away from....
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A very loud sweeping siren type audio sound generator powered by 3v. The circuit uses a LTC1799 precision frequency generator from Linear Technology. A 74HC14 hex Schmitt trigger from Texas Instruments is also used to perform several other functions. One....
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This oscillator is called the Colpitts oscillator and voltage controlled to achieve the FM (frequency modulation) and PLL control. T1 must be HF transistors to work well, but in this case I use a cheap and common BC817 transistor. LC tank oscillator needs to....
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Wireless FM Transmitter. The site has some explanation on how the circuit works, however I`m not sure about a few things, including the electret mic & how the frequency modulation takes place. The electret microphone has a current of 200uA which changes by....
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The audio mixer schematic we propose is developed arround 4 amplifiers build inside SSM2024 produced by Precision Monolithics Inc. (PMI) and is voltage controlled (VR). The maximum VR voltage is 5. 5Volt. The signal/noise ratio is 90dB and 130Khz band wide.....
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Ok, I have been looking for this circuit on line now for a while and I finally found it. (Thank you Kostas 711 in Patras City, Greece. ) Turns out it is a pretty simple circuit. Part of it is a voltage regulator and filter to isolate the voltage supplied by....
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Q1, Q2 & Q3 form a high impedance super-Darlington that drives the relay, amplifying the 50 or 60Hz alternate mains-supply frequency induced in the sensor by the human body. C1, D2 & D3 ensure a clean switching of the relay. Power supply can be any....
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This is a 25 Watt basic power amp that was designed to be (relatively) easy to build at a reasonable cost. It has better performance than the standard STK module amps that are used in practically every mass market stereo receiver manufactured today. When I....
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The gate N1 acts as a buffer for strengthening the signals from the condenser microphone. The inverter N2 with its associated components forms a radio frequency oscillator in the FM region. The varicap diode BB109 is used for frequency modulating the audio....
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This device was designed on request and allows sequential operation of four Leds either to left or right direction, obtained by means of a 7555 CMos timer IC (IC1) wired as an astable multivibrator driving a Decade counter (IC2). This IC is set to count a....
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Most of people ask TV transmitters. So Today I`m going to give you a very useful circuit diagram. By using this circuit you can send your signals 75m to 100m. This circuit diagram is not my own circuit one of my friends gave me this. I suppose you guys also....
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