Popular Circuits Page 237
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Using an ISD1016 audio record/playback chip (Information Storage Devices, Inc.), this circuit records and plays back messages on command. Although intended for use with transmitters, it can be used as an electronic notepad, etc. ..
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This unit provide 2 way IR communications using a numeric keypad and an LCD display. Data is sent and recieved in ASCII with no regard to what the data means to any particular device. The ASCII data still needs some form of encoding. For this I chose....
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The remote control receiver is a custom design based on a pre-built 433MHz UHF radio receiver, a decoder chip and a BASIC Stamp. The Stamp is expensive, but easy to work with. The receiver requires 8.5mA, plus 1.5mA for each LED (individual or segment) that....
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By analyzing the filter capacitance or inductance is filtered DC output is still more or less volatility. In situations requiring high level..
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I get a lot of questions about wiring motorcycles. Sometimes people are just trying to fix their blinkers and aren`t familiar with how motorcycle electrics work but more often than not I get requests about trimming down electronics for custom riders. An....
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When a network needs to transfer small blocks of information over long distances, RS-485 is often the interface of choice. The network nodes can be PCs, microcontrollers, or any devices capable of asynchronous serial communications. Compared to Ethernet and....
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Simple PWM inverter circuit using SG3524. This PWM inverter circuit has 12V input, 220V output and 250 watt output power. Output power can be extended....
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This circuit is the opposite of Repeating Timer No.5. It will only begin to operate if the temperature falls below the preset level. Again - the variable resistor (preset) lets you choose the temperature below which the timer will function....
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Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmitter can transmit speech over a short range. It can be used as a simple cordless microphone. The circuit uses two....
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There are a number of ways to obtain the low voltages required to run small projects from the wall power outlet. The simplest way is to buy a factory-built molded supply which is designed to plug directly into the wall outlet. Some such supplies have an....
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The example program included with the PG2051 evaluation kit is a basic serial to parallel converter written in 8051 assembler. This is probably a good example of the uses to which an AT89C2051 can be put - it would be hard to get a serial to parallel....
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This is an improved IR remote control extender circuit. It has high noise immunity, is resistant to ambient and reflected light and has an increased range from remote control to the extender circuit of about 7 meters. It should work with any domestic....
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Oatley Electronics in New South Wales Australia makes a few kits based around the Raytheon JAN 6418 sub-miniature valve (tube). I decided to try out the $27AU K272A Stereo Tube Preamplifier - Headphone Driver kit. [Note - the K272 has been replaced with the....
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This is a circuit which can detect any motion or movement. It`s most common use is to detect a person moving through an area where the motion detector can sense. The main electronic component we will use that allows us to pick up this detection is the PIR....
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After charging the batteries for many hours with the 12V charger and PowerCheqs, I drove for about 5 miles and the low battery light came on. PakTrakr showed that the battery next to the most positive battery needed recharging. Apparent that battery is bad,....
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An output of 4 mA to 20 mA that is linearly proportional to the input voltage is provided by the current transmitter on figure below. Line rejection is...
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This circuit shows about LM2576T IC Step-Down Switching Power Supply Circuit Diagram. Features:60V input voltage, 3.3 V/5V/12V/15V output ....
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When listening to music at low volume levels, bass and treble frequencies are attenuated more than mid frequencies. This loudness control alters the frequency response curve to correspond roughly with the equal loudness characteristic of the ear. The circuit....
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Zener diode ZD1 senses the supply, and should the supply rise above 6 V, Ql will turn on. In turn, Q2 conducts clamping the rail. Subsequent events depend on the source supply. It will either shut down, go into current limit or blow its supply fuse. None of....
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This project`s purpose is to design a fully automated machine for drilling a printed circuit board, (PCB) blank at a minimum cost and with the minimum amount of custom machining. This low cost philosophy is achieved by adapting the existing mechanical....
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The Intersil ISL43485 is a high speed BiCMOS 3. 3V powered, single transceiver that meets both the RS-485 and RS-422 standards for balanced communication. Unlike some competitive devices, this Intersil transceiver is specified for 10% tolerance supplies (3V....
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A truly timeless circuit. LM317 is a versatile and highly efficient 1.2-37V voltage regulator that can provide up to 1.5A of current with a large heat sink. It`s ideal for just about any application. This was my first workbench power supply and I still use....
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This circuit passes the input signal at unity gain, either unchanged or inverted, depending on the digital control input. A buffered input is shown, since low-source impedance is essential. Gain can be added by modifications to the feedback networks.....
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Many of my friends asked me for automatic on off led circuit or led flashing circuit so here I`m going to post a Astable multivibrator-2 LED flashing circuit. It is a simple astable multivibrator circuit using 2LED (here i used red LED), two NPN small....
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The circuit is quick and easy to put together and install, and tells you when battery voltage falls below the set limit as established by Rl (a 10,000-ohm potentiometer). It can indicate, via LED 1, that the battery may be defective or in need of change if....
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The tester gives an audible indication, making it unnecessary for the user to look directly at the instrument to observe a meter reading. In addition, the current and voltage of the tester are strictly limited. It can apply no more than 0.6 volts dc and no....
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This can be a thin strand of wire, like one of the copper "hairs" from a section of lamp cord, which is wired to the altimeter by terminals somewhere on the rocket body and anchored to the launch stand at some point. Rocket takes off, stand holds the wire....
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In essence, this circuit is a 15 to 20-second courtesy light extender for cars. It is activated in the usual way by opening a door but it also samples the negative lock/unlock signals from a car alarm or central locking and does two more things. First, when....
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FET several basic bias circuit - self bias voltage divider circuit ..
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A reasonably effective bfo (bifilar oscillator). Its performance is not comparable to more advanced commercial products, of course, but it still works. Anyway, during WWII metal detectors based on the same principle were utilized my combat engineers of many....
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ABSTRACT The aim of the project is to avoid vehicle collision. We can avoid these things by using ultrasonic anti-collision instrument. This instrument is fixed in front side of the vehicle. If any vehicle or obstacle comes near by this vehicle...
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This circuit is a circuit diagram of the radio-controlled, usually in the toy car application children. Circuit diagram consists of 2 parts of the circuit sender and receiver circuits. To the circuit sending radio signals generated by the oscillator circuit....
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The following diagram is the schematic diagram of Ni-CAD Battery Charger circuit which featured with current and voltage limiting to keep the battery lifetime. The lamp L1 will be light brightly and the LED will be out when the battery is low and battery....
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Wanting to use two white LEDs, the second device must be wired across the Emitter of the transistor and negative ground with its own limiting resistor wired in series, like R15 and D3 in the circuit diagram. If common red, yellow or green LEDs are required,....
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This frequency counter uses your existing digital multimeter as the display unit that is why it can be constructed at very low cost. Due to the high impedance of most DMMs, a frequency to voltage converter can be easily connected to it without matching....
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This circuit generates 3 source regulated voltages applying a minimum of electronic parts. The output DC voltage are +12V ; +5V and -5V. Diodes D2 and D3 conduct full-wave rectification, at the same time charging capacitor C2 on each halves of the....
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This is the project home page of the SmaTrig 2. 1, the improved version of the the SmaTrig 2. On this site you will find complete instructions how to use and build the versatile and compact (27 gram) 15-in-1 camera trigger SmaTrig 2. 1. Everything needed to....
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For the regulation it needs a voltmeter (with needle better) and charge 50W/5W. Connect charge 50W in the place of aerial, with the voltmeter in the exit voltmeter. Be supplied the transmitter with + 12V. It will be supposed we have consumption between....
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The JFETs, Ql and Q2, provide complete buffering to Cl, the sample and hold capacitor. During sample, Ql is turned on and provides a path, rds(on), for charging Cl. During hold, Ql is turned off, thus leaving Ql Id (< 100 pA) and Q2 Igss (< 100 pA) as the....
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Take the input from a microphone and use it to power an LED, so that it`s off at ambient sound, and (the peak brightness) gets brighter with noise level. It`s okay if it flickers, I`m just trying to get the peak voltage to be proportional to sound levels.....
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The first one I bought for US$ 3. It has an internal rectifier, and even after I dug it out of the epoxy, performance was still poor. The next two were given to me by the ever kind and helpful Francis Rutherford at the Regional Occupations Program and....
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Many integrated circuits have undocumented features or abilities. This is one of them. The TLC555 output (pin 3) can sink a 100mA load to 1. 28V. The open drain transistor reset (pin 7) can sink 100mA to 1V. Tying both lines together is permissible because....
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This IR remote extender can increase the range of most simple IR remotes (those operating on a 40KHz modulation) a significant distance. In use, the remote is pointed toward the detector on the circuit, and a button is pressed. The Sharp IR detector then....
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The following circuit shows a timer circuit with independent mark and space periods. This circuit based on the 7555 IC. Features: output high is calculated by T(on) = 0. 7 Ra Ct, output low is calculated by T(off) = 0. 7 Rb Ct, astable timer, (on) and (off)....
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How many different conditions do you reckon may be signalled with just one LED Two, maybe three Using this simple circuit, a lot more! Admittedly, a two-colour LED is used here. Such a device consists of two light-emitting chips, usually red and green,....
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A portable phone charger for a Siemens mobile phone. Since I don`t use that phone anymore and recent phones can usually be charged with a USB connector I built a new version of the charger. This time with a proper PCB, a USB connector and a higher current....
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The transistor switches ON and pushes the magnet away, and at the same time the transistor switches off, the stored energy in the coil is going to collapse and the only way it can go is into the charging battery. The next magnet arrives, and the process....
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Both parts of the circuit are biased with the constant current sources as shown, and the signal from the collector of the PNP is followed by the Darlington class A output stage whose idle current is controlled by the bias circuit. The transistors Q1 and Q2....
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When activated by pressing a button, this time delay relay will activate a load after a specified amount of time. This time is adjustable to whatever you want simply by changing the value of a resistor and/or capacitor. The current capacity of the circuit is....
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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 employs the ADC (Analogue to Digital Converter) I. C. CL7107 made by INTERSIL. This....
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This unit uses switches and resistors to provide a number of current ranges. It allows you to test most of the meters availabl..
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The contact less telephone ringer circuit can produce a ring as well as a visual indication when a call comes. The main advantage is that since there is no direct contact between the phone line and the circuit there is no chance for a loading or disturbance....
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This smoke detector circuit diagram is based on the SD2 CMOS Photo-Electric Smoke Detector Integrated Circuit manufactured by Supertex INC and include almost all needed components to build a very simple and high efficiency smoke detector project. The LED....
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Many beginners trying out their skill with QRP TX, for the first time have to overcome many problems before they are able to come on the air. On usual complaint is that, every thing is working fine but the signal is not going out. Here is a simple set up....
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A DIY intervalometer for my Sony NEX 5N camera so that I could do time-lapse photography. This intervalometer should work with most Sony cameras: NEX, Alpha and other. To work intervalometer used infrared LED Serial LCD has 4 output: GND, VCC, SDA, SCL. SDA....
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This is about as close as you can get to a real vintage Pultec EQP-1a. Built from the original Pulse Techniques Pultec schematic with the layout designed around modern replacement parts (filter caps and trannys); and utilizing best practices regarding lead....
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For it`s maximum result, the final stage of the amplifier should have the proper power supply, as the flowing, currents are very high. An Class A amplifier, requires attention. These are the rules for the power supply for the Class A audio amplifier. The....
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AD, I70 is a signal conditioning integrated circuit RTD/PRTD design, it is very suitable 1K, lOOfl platinum RTD (PRTD). ADT70 internal integration of the instrumentation amplif..
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This is the first electronic circuit I designed from scratch, my first time programming a MCU, the first time I wrote an application in assembly language and my second homemade PCB. Usually people starts building very simple things and they increase the....
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Transistors Ql and Q2 are connected as a free running multivibrator. The output, at the emitter of Q2, drives the base of the common emitter amplifier Q3, which controls the lamp. This circuit configuration permits the flash duration, the interval between....
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Present roads in good condition than the former Pan. The traffic is convenient. But often ran high speeds. When we use the bicycle at night. Although the...
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This is the circuit diagram of a 3 LED bar graph type battery monitor circuit that is ideal for monitoring the voltage level of an automobile battery. When battery voltage is 11. 5V or less transistor Q1 will be On and the LED D1 will be glowing. When....
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The CS4811 is a complete Audio effects processing system on a chip. This device integrates a proprietary 24- bit Audio processing engine, large on-chip RAM Memories and a high performance 24-bit Audio CODEC A serial control port allows the device to boot....
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I would like to build a board that has 1 - 120volt/600Watt input and > 3 - 120volt/200Watt outputs. The outputs we shall call A, B ....
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This simple tuned radio frequency receiver (Fig. 1) was designed and constructed in the mid 1990s. The receiver was tested under urban and field conditions, in the heat and cold. This simple circuit has quite high sensitivity, good sound quality and....
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By the main speed setting box FR-FG and the linkage setting operation box FR-AL (Mitsubishi inverter) multi motors synchronous operation. Circuit is shown. Using these two exte..
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Here is a circuit that implements phase-control of heaters, adjusting their power smoothly from zero to around 95% of the rated power, keeping the room temperature to within 1 or 2 degrees, while using few components. Notice that this is entirely an AC....
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This is a low cost way of measuring temperature and humidity with a computer interface and is intended to be an entry level project for high school students on a tight budget. ..
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Circuitdiagram of marine tv dishe. circuitdiagram of marine tv dishe, circuitdiagram of marine tv dishe, 12dc to 120ac inverter circuitdiagram pdf+, 12dc to 120ac inverter circuitdiagram pdf+....
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Dual motor drive circuit Automatic tracking shows are constituted by two motors (white line) Cars structure, principle and double motor drive circuit. ..
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Intercom or Inter communication circuit is a two directional communication system. It provides a reliable communication line and is extremely easy to implement. The circuit is prepared by an amplifier, two switches and two loudspeakers. We can extend this....
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The simple circuit in Figure 1 uses a low-current-drain MAX4073H amplifier to sense the current flowing through a 4- to 20-mA loop. The circuit senses the current through a 1 resistor with a fixed gain of 100 and uses no battery or dc power supply. The low....
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One preset resistor is used for all the ranges, simplifying the setting up. Diode clamping is included to prevent damage to the meter if the unknown resistor is higher than the range selected..
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This is the lowest cost dialing alarm on the market and shows what can be done with an 8-pin microcontroller. The complete circuit is shown below. You cannot see all the features of this project by looking at the circuit - most of them are contained in the....
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The main circuit uses a two-input NAND gate four digital integrated circuits, wherein the composition..
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The circuit was designed to produce a circuit that will alarm a sleeping person to prevent snoring by using a vibrator instead of an audio alert so as not....
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A two-circuit tuner, as the loose coupler, is one of the only ways selectivity can be accomplished without sacrificing sensitivity. Let`s look at the circuit, see figure #8: The signal is introduced to the primary antenna section via SW-1 arrangement, in....
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This is a 220V Touch Switch circuit. This circuit is used as switch which turn off and turn on the the electronic device that is connected to the 220V home....
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The charger is based on a charging voltage of 2.4 V per cell, in accordance with most manufacturers' recommendations. The circuit pulses the battery under charge with 14.4 V (6 cells ? 2.4 V per cell) at a rate of 120 Hz. The design provides current limiting....
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Lamp LI will glow brightly and the LED will be out when the battery is low and being charged, but the LED will be bright and the light bulb dim when the battery is almost ready. Ll should be a light bulb rated for the current you want (usually the battery....
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Door intercom is very useful for home security. If you receive a door knock or door bell/alarm, you can push this intercom knob and ask the guest? to identify...
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The GPS Car or Boat Computer can display a wide range of GPS related information for the driving or boating enthusiast. In this page you will find everything that you need to know to build the unit. This includes the design, schematic, parts list, PC board....
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Using the ISL9440 quad-output synchronous buck controller IC can be designed a very simple high efficiency electronic circuit power supply, that will provide 4 different fixed output voltages. ISL9440 synchronous buck controller circuit integrate 3 PWM....
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IC1a and IC1b are wired as a slow astable multivibrator and IC1c-IC1d are wired as a fast astable. Both are "gated" types, which can be turned on and off via PB1. The output of the slow astable modulates the frequency of the fast astable, and the output of....
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1B32 application circuit with multiple pressure sensor shown in Fig. Excitation power through AD542, after TIP32 then drive multiple bridge sensors. AD542 is a Bi-FET as the in..
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Chris has a great article about a do-it-yourself radar system build with PIC18F452. It s a great hobby project although the schematic....