Popular Circuits Page 118
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This mic preamp uses the low noise IC uA739. The circuit is an example of how a good preamplifier can be designed for dynamic microphones. The IC houses two identical integrated preamp circuits. The second preamp is used in identical manner for the second....
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14 watt equivalent light with just 1. 2 watts input. No, the light will be brighter and brighter as you approach the watt rating of the CFL bulb. What`s remarkable is that this circuit can light this CFL at very low voltage or higher too. A dimmable CFL is....
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DW10M de-excitation type switch is based on the DW10 automatic air circuit breaker on the normally open to normally closed contact is made. (1) DW10M-200,400, 600 de-excitation..
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In this strobe-light, two circuits are needed; one circuit charges a capacitor placing 320 V de between the cathode and anode of the flashtube. The other circuit provides bursts of approximately 4000 V to trigger the flashtube into conduction. The....
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USB HID is a specification that includes things like mouse and keyboard. has a GPL based driver to implement USB in an avr microcontroller without specialized hardware. There is also the AVR309, software USB application note from Atmel. I don`t know who....
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With IC SLB0586A from Siemens you can build a simple touch light dimmer circuit that will allow you to adjust the lamp intensity. Together with a TIC206D....
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A localizer without GPS. We remake the old device with the cheaper SimCom module SIM900. In the previous post we present the GSM section and now we can present the complete localizator. This system allows for localization without directly using GPS....
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Bipolar stepper motor drive circuit is shown, it will use eight transistors to drive two phases. Bipolar drive circuit can drive four-wire or six-wire stepper motor, although t..
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This circuit enables a single SCR to provide fullwave control of resistive loads. Resistor R3 should be chosen so that when potentiometer R2 is at its minimum setting, the current in the load is at the required minimum level..
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This is the easy build surround sound processor circuit using the digital delay process method. This audio processor isn`t applying any unique function ICs that tough to obtain parsonaly, and designed in only common purpose ICs. The kind of this Surround....
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Electric single-girder cranes is also known as electric hoist. It is commonly used in small factories lifting handling equipment. Usually it is always used with drag line switching noytoperation, which is not very convenient. The circuit is composed of radio....
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It is annoying to realize that you have left your car headlights on only to find that the battery is flat. One possib..
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Electrical potentials are generated by muscle when there is movement. This Signal can be pick up by electrode to form EMG. For my Final Year Project, I did an amplifier and signal conditioning circuit for EMG. Attached below is the schematics for the....
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The mechanical chassis prototype, as can be seen from the image on the left, was made using two materials: foam and aluminium. Foam was chosen due to its easy manipulation and aluminium due to its excellent strength to weight ratio. The prototype includes a....
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Friends that seek 5V 10A power supply circuit small-sized and build easy. I begs for to advise this circuit. It is 10A switching regulator by use IC L4970A. Then build easy as an example integrated readymade circuit. Important point be power supply input....
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One of the major problems that is to be solved in an electronic circuit design is the production of low voltage DC power supply from Mains to power the cir....
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As shown in Figure it is 567 FM demodulation circuit. In the figue, the FM signalenters from the 3 foot, the demodulated signal goes out from 5 foot. FM signal center frequency which the circuit can demodulateis: fo = 1.1 / RC, C1 isfilter capacitor, and C2....
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The circuit below is configured as a comparator. A fixed reference voltage at the non inverting input is provided by R1 and R2. The inverting input voltage is....
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An NTSC/RGB decoder is shown here. Using a TDA3330, 1-V input video is broken down into its R, G, B components, and composite synch. U1 is an integrated synch separator (LM1881). This circuit should be useful for interfacing RGB monitors to NTSC video....
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This circuit operates by charging a small capacitor from a constant-current source when the pulse to be measured is present. Dual pnp transistor Q3 is the current source; its output current equals the LM329 reference voltage divided by the resistance of....
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I built this circuit and for some reason it works. FYI, the diodes are red 5mm LED`s, the transistor is 3904 NPN, and the resistors are what are shown in the schematic. Logically it should not work when you press the PBNO. The red 5mm diodes should be....
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This circuit can be used to monitor the voltage level of a car battery. When the battery voltage is 11. 5V or less the transistor Q1 is on and D1 glowing. When LED battery voltage is between 11. 5 to 13. 5 V, the transistor Q2 is on and the glowing LED D2.....
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Most ohmmeters of the design shown in the previous section utilize a battery of relatively low voltage, usually nine volts or less. This is perfectly adequate for measuring resistances under several mega-ohms (M ©), but when extremely high resistances need....
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Indicator was designed for displaying the peak level of small ac signals from a variety of transducers including microphones, strain gauges and photodiodes. The circuit responds to input signals contained within the audio frequency spectrum, i.e., 30 Hz to....
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The first two are `passive` elements and op-amp is an `active` element. Also: the first two are `two-terminal` elements and the op-amp is a `three-terminal` element. Resistor has the ability to define the current that flows through it when a voltage is....
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This circuit measures the distance covered during a walk. Hardware is located in a small box slipped in pants` pocket and the display is conceived in the following manner: the leftmost display D2 (the most significant digit) shows 0 to 9 Km. and its dot is....
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As shown in (a), KAi, KA2, KA3 intermediate relay, connected to the outlet end of the low-voltage circuit breakers total. Alarm circuit connected to the backup power supply or ..
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This circuit uses just one IC and a very few number of external components. It displays the audio level in terms of 10 LEDs. The input voltage can vary from 12V to 20V, but suggested voltage is 12V. The LM3915 is a monolithic integrated circuit that senses....
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Circuit shown in Figure 3-47. Close the power switch os, operating handle to push the start position, then three-phase AC motor is connected through a step-down autotransformer..
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The resolution of the barometric pressure is about 0. 00417 inHg (0. 0139 kPa) for a pressure range of 31. 0 to 28. 0 inHg (105. 0 to 95. 0 kPa, or 1050 to 950 mb or hPa). Better resolutions are possible with a more restricted pressure range. The circuit....
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This alarm system has 6 independent zones, 1 timed entry/exit zone, a 7 segment LED display and a test or walkthrough facility. Suitable for a small office or home environment, it can also be adapted to use a combination lock or keypad to set and reset the....
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Electronic Schematic Circuit Diagrams Manual PDF Download...
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Used a 12V motorcylce Battery and an ignition coil of a car. A microcontroller produces some pulses to the base of a 2N3055 transistor. 2N3055 turn on an off the primary of the coil and the desirable sound is produced between the probe and the surface. I....
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Digital Code Lock with efficient hacking prevention from Brute Force etc. The basic user lock is of 5 Digits and Master Lock is of 10 digits so its not easy build Digital Code Lock Project Jaipur, Create Digital Lock Project jaipur, electronic code lock,....
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D2025 Dual audio power amplifier circuit D2025 is a stereo audio power amplifier integrated circuits, power amplifier for use DIP16 package applicable to all types of portable ..
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I am presenting you a simple smoke sensing alarm circuit using 555 timer. By using this circuit you can detect smoke and it alarms when the air is contaminated. Let me introduce you the components used in it. This smoke detecting alarm is based directly on....
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This is a circuit that is known as wien bridge oscillator circuit. The circuit has positive and negative feedback loop. This circuit is work with control by op amp. This is the figure of the circuit. The circuit oscillates at a frequency determined by the RC....
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The following circuit shows about Ni-Cd Battery Charger Super Fast Circuit. Features: based on the IC MAX 712, Ni-Cd battery at 3oomA, charging ....
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The basic concept as I understand it, is a high frequency high voltage low current rectified and then used to charge a bank of high value capacitors and then to discharge them in pulse mode for brief period of time, nano seconds in fact by, means of a high....
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A keypad enters a four-digit access code, which is programmed via jumpers on a 24-pin plug-in header and socket. U1 is an LST220, which detects a four-digit sequential data input. When the correct data is entered into the keyboard, pin 13 of U1 goes high,....
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This circuit is used to trigger a camera`s electronic shutter circuit when a flash of lightning is present. This circuit would also work for photographing fireworks displays or other events involving flashes of light...
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PIC microcontrollers are a very useful and versatile tool for use in many electronic projects. They are very inexpensive and easy to find. They are al....
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The 555 timer is so named because its primary mode of operation is intended to be in monostable mode. Operating as a monostable, it does not fit the strict definition of an oscillator because, unlike true oscillators, it requires an input signal to trigger....
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This is a nice LFO for all of your modulation needs. The frequency can be voltage controlled to add a new dimension to your sound palette. The pulse width of the rectangle wave can be varied between approximately 10% and 90% again lending variability to the....
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This circuit is for low voltage applications requiring high power outputs. Output power levels of LO W into 4 ohm from 6 V and 3 V into 8 ohm from 12 V are typical. Coupling capacitors are not necessary since the output dc levels will-be within a few tenths....
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This project is really a mixture of ideas, some simple, and others even simpler. The system I have installed in my biamp unit is fan cooling. Once a preset temperature is reached, the fans start, and remain on until the amp is turned off again. This is....
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The purpose of this circuit was to create a ring in which LEDs or Lamps illuminate sequentially. Its main feature is a high versatility: you can build a loop containing any number of LEDs or Lamps, as each illuminating device has its own small circuit. The....
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The graphic equalizer circuit the frequency adjust circuit. For some kinds of audio frequency response is not smooth. The....
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At around 50 Khz i can get over 40 volts at the receiver. Light`s LED`s no probs. It even blew a 5mm LED. The cap I had on the AC was blocking the energy. Anyway what I did was connect the primary negative to ground with the secondary on the transmitter, a....
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A wonderful diy gsm jammer or cellular mobile phone jammer schematic diagram for use only in GSM1900 with frequency from 1930 MHz to 1990 MHz. The GSM1900 cellular cell phone network is made use of by USA, Canada and most of the nations in South America.....
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This stage may be driven by another resistance coupled amplifier stage in which case the resistor on the left labeled RC is RCf for the previous stage. The resistor on the right labeled RCf is the grid resistor of the next or following stage. The resistor....
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A NE555 IC is used for designing the variable low frequency oscillator and schematic is also given....
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A opamp medium power, used as amplifier of headphones with possibility drive low loads. It contains in a nutshell two amplifiers. The voltage gain, has been determined in 40dB, from the R3-4 and R11-12, for each channel, respectively. The restriction of....
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The project explains how to make simple AVR High Voltage Programmer using Arduino. It can be used to fix/recovery wrong fused AVR chip....
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TDC1808/TDC1809 is a pair of wireless remote control transmitter and receiver component. They use an internal antenna, transmitting digital signals or analog signals. It is suitable for a variety of wireless remote control device. The features are small....
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What is A pH Meter? A pH meter is actually a precise voltmeter that measures the generated voltage of a pH electrodes. The requirement of such meter is high....
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Generating long delays of several hours can be accomplished by using a low frequency oscillator and a binary counter as shown below. A single Schmitt Trigger inverter stage (1/6 of 74HC14) is used as a squarewave oscillator to produce a low frequency of....
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This circuit is mainly intended to provide common home stereo amplifiers with a microphone input. The battery supply is a good compromise: in this manner the input circuit is free from mains low frequency hum pick-up and connection to the amplifier is more....
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Capacitive touch sensors are based on the electrical capacitance of the human body. When, for example, a finger comes close to the sensor, it creates a capacitance to Earth with a value of 30 to 100 pF. This effect can be used for proximity detection and....
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This is a Preselector for SW receivers (diy hf preselector) circuit. The entry low capacitance of MOSFET modern, with two gates, will create negative inverse reaction through a uncoupled source resistor. Applied right this technique allows the creation of a....
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This project is a piece of test equipment. It`s a square wave oscillator with 6 selectable frequencies from 1Hz to 100kHz, incrementing in decade values. It`s most useful application is as a Signal Injector for radios and TV`s. A square wave is the most....
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I`m making a small DC tesla coil with a rotating spark gap. The motor controlling the RSG draws about 3. 8 amps of current at full load, and the 555 control circuit and amp draws about 4 amps. Would it be best to run the motor and 555 circuit parallel from....
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This two-zone alarm has automatic exit, entry and siren cut-off timers. It was developed for the Beginner`s Guide To Cmos Timers. So it has a particularly detailed circuit description. There`s an optional One-Time-Only module. It will force the siren to....
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Describes how to layout switch-mode DC-DC converter printed circuit boards (PCBs) to minimize switching noise and EMI....
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The add-on circuit presented here is useful for stereo systems. This circuit has provision for connecting stereo outputs from four different sources/channels as inputs and only one of them is selected/connected to the output at any one time. When power....
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When testing circuits with a logic probe, it is sometimes difficult to watch the LEDS on the probe to determine the logic state. With this probe the logic states are audible. This probe is designed for TTL circuits only but could be modified for CMOS. The....
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At certain times of the year I migrate a bit North of Southampton to an area where the the hams on VHF are grumbly and seem to be few and far between. Add to this that the local repeater only uses tone burst and that the QTH is right next to some noisy....
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As shown by FIG MAX4450/4451 unity gain line in the driving circuit. MAX4450/4451 has internal compensation, a 24 resistor in series in a feedback loop, capacitors, and inducto..
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Sometimes, you need to remotely turn on or off a two-state system, such as a light, from multiple points. You could connect simple pushbutton switches in parallel to a single-line bus. However, if the bus simply controls a toggle flip-flop, the system must....
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This circuit charges the battery at 75 mA battery can be left in the charger indefinitely, until the battery is charged, then it reduces the To set the shut-off point, connect a 270-ohm, current to a trickle rate..
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This is a simple FM transmitter circuit schematic diagram with a single transistor S9014....
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The low-cost circuit in Figure 1 allows you to track four remote temperatures with thermistor sensors through the parallel port on your PC. This four-zone thermometer instrument has a temperature range of 40 to +90°C and a resolution of better than ±1°C. You....
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In intrinsically safe applications, it is sometimes necessary to separate sections of circuitry by resistors which limit current under fault conditions. The circuit shown provides an accurate analogue output with effectively zero output impedance, despite....
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3 channel audio mixer circuit uses voltage 9VDC summber which can supplied from a battery. 3 channel audio mixer circuit is designed special for the purposes of this Public Amplifier. Because the audio circuit of this mixer is designed specifically for the....
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The mixer appearance two stereo phono inputs and two stereo line-level inputs and has one stereo bond channel. A microphone ascribe and a stereo capital achievement with adjustable accretion are additionally provided...
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A very simple battery charger circuit having reverse polarity indication is shown here. The circuit is based on IC L200. L200 is a five pin variable voltage voltage regulator IC. The charging circuit can be fed by the DC voltage from a bridge rectifier or....
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This timer circuit will only run when the temperature rises above a preset level. There`s an alternative version - Repeating Timer No. 6 - that only works while the temperature is below the preset level. R7 lets you set the temperature. The value of the....
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This very simple, low cost oscillator, is built with two CMOS buffer inverters, two capacitors and a variable resistance. The circuit can work with voltages ranging from 4 V up to 18 V. If Cl = C2, the frequency of oscillation.
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This circuit is used to meter the audio power output of an amplifier feeding a speaker. RY1 is actuated if excess ..
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learn to use microcontrollers to create traffic-light applications. In this project we will use microcontroller AVR-007 from Circuits-Home. Before creating the program, the first job we have to do is understand about the hardware specs...
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Hall-effect switches have several advantages over mechanical and optically coupled switches, They"re insensitive to environmental light and dirt, they don"t bind, and they don"t sustain mechanical wear. Their major drawback is that they require three wires....
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40 meter Direct Conversion Receiver. Using the circuit of 40-metre band direct-conversion receiver descr- ibed here, one can listen to amateur radio QSO signals in CW as well as in SSB mode in...
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The zener provides a constant voltage of 20 V to unijunction transistor Ql, except at the end of each half-cycle of the input when the line voltage drops to zero. Initially, the voltage across capacitor Cl is zero and capacitor C2 cannot charge to trigger....
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This circuit is a frequency meter, low cost. It covers region 1HZ until 1MHZ. The IC1 schmitt trigger that it regulates the signal of entry and him changes in reasonable level suitable for the IC2-3-4. With the tenth pulse in the entry of IC2/1, is produced....
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One day on the 50MHz SSB-QSO, my friends JE3TXU/1 (Mr. Haraguchi) sad to me that he made 50MHz very small transceiver. I said to him that he shall inform about it on the Japanease CQ magazine. You can see about it on the book. See the photo! This rig is made....
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As shown in FIG circuit protection circuit is the use of optocouplers or not the on-off control. Voltage is normal, almost no output optocouplers, VT pipe is reverse biased and..
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It`s well known that many animals are particularly sensitive to high-frequency sounds that humans can`t hear. Many commercial pest repellers based on this principle are available, most of them operating in the range of 30 to 50 kHz. My aim was, however, to....
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The chip tester verifies the functionality and timing of a variety of 7400 series integrated circuits. Students taking Digital Logic Design Lab, Use these chips often in their laboratory.
The IC to be tested should be placed on the ZIF socket and the....
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