Popular Circuits Page 189
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This circuit provides a visual indication of the input analog voltage level. It has a high input impedance at pin 8 and open-collector outputs capable of sinking up to 40 milliam-peres. It is suitable for driving a linear array of 5 LEDs to indicate the....
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The generator described here is intended for multiburst signal square waveform generation and can be used as a device for characterizing the response of TV monitor amplifiers as shown. The circuit is an RC oscillator with NAND gates (IC4-4011), with its....
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The tester consists of a rectifier circuit and a multivibrator circuit. The ac voltage is half-wave rectified by diode D1 and stored in capacitor CI. Resistor Rl is used to limit the current through D1 to a safe value. The voltage stored across CI supplies....
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After the recent pretty disappointing results with a transformer-based Component Tester, I`d like to try and generate a ± 10 V sine wave at approximately 50 Hz in some other way. Using as few components as possible. This is where we enter, eh, squarely into....
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Built around an LM380, this amplifier includes tone controls and electronic "soft switching". The soft switching circuitry ensures power is built up gradually eliminating the dc thump. The soft switching is enabled by a BD131 transistor wired as a switch in....
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This converter allows coverage from 25 kHz up to 500 kHz. Use short coax from the converter to receiver antenna input..
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The I.F. amplifier is similar to the one used in the 80M receiver project . The original design has been modified by putting a couple of LED`s in the source circuit of each Mosfet. The voltage drop across the LED`s keeps the source voltage at about two....
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Here`s a nifty sound level meter is a perfect one chip replacement for the standard analog meters. It is completely solid state and will never wear out. The whole circuit is based on the LM3915 audio level IC and uses only a few external components. This....
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By the regulator circuit output voltage of the potentiometer Rp, and has a linear regulation characteristics. Figure (b) shows the output..
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The following circuit shows about Current Limited Solar Battery Charger Circuit Diagram. This Lead Acid or Ni-Cd Battery Charger Circuit Diagram utilizes solar energy to charge a 6 volt 4. 5 Ah rechargeable battery for various applications. This is a great a....
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The following circuit shows about NE555 Timer For Electronic Scooring Game Circuit Diagram. Features:The circuit comprises a timer IC, with a ....
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Circuit works: When normal inspection work where the voltage across the resistor R2 through, RP, partial pressure, as the input signal of IC4. IC4, R3 ~ Rg,..
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Gyrators find application in DC holding circuits which are used in most DAAs (Data Access Arrangements). DAAs typically use dry transformers which can not tolerate DC current, and incorporate a DC blocking cap. When the telephone goes off hook, it must pass....
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A 15 watt amplifier made using discrete components. Sergio designed this circuit for his Electronics Level II course...
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The ramp generator, an inexpensive alternative to commercial function generators, provides a more linear and repeatable output than conventional analog integrators. The circuit provides a triangle waveform in burst mode; in this case, two cycles of 10.24....
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The transmitter on 2 meters 144 MHz was designed mainly for use by radio amateurs as radio beacon and to this end, it produces a signal of good quality and....
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Self-designed amplifier circuit 9 of the circuit described in this article is completely symmetrical and complementary, can give full play to the..
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The proposed mixer is designed around four current-driven transconductance amplifiers contained in an SSM2024 from Precisio..
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Motor windings are scheduled to join Y Rong, while L IS ON, 2JC {}} electric suction, Union minister motor Y} i pick Save iIf /) f ~ tjj. ON 115 causes JMP - S also coat LU r + ashamed, to turn the motor was built gun delete, turn a motor built escape Wu j l....
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This circuit uses a ring counter made up of Q3, Q4 and Q5. Q2 acts as an oscillator which triggers the SCRs Q3, Q4 and Q5 in sequence. When an SCR fires, a 0.2µ¥ capacitor provides commutation, shutting off the previous stage...
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This circuit came from a need for a quick and dirty network tester that could be operated by one person. All the commercial units I tried required a per....
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Writing MCU assembly code is often a hard and tedious task. You can simplify software development and gain more time to design the electronics hardware if, instead of manual coding, you use TINA`s Flowchart editor and debugger to generate and debug the MCU....
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Transmitter operation. Operating power for the transmitter circuit is derived directly from the ac line. The dc power to operate the circuit is generated in two stages, one for an RF power-am-plifier stage, and the second for the remainder of the circuit.....
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This circuit is a temperature controlled version of Repeating Timer No.3 . The light dependent resistor has been replaced by a temperature dependent resistor or thermistor. And a small preset potentiometer lets you choose the temperature above which the....
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First you need a mechanical power source like a turbine(powered by water falling), wind turbine, gas turbine or steam turbine. A shaft from one of these devices is connected to a generator to make power. Dynamos and generators work using the wild complex....
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Charge NiCd or NiMH batteries with solar cells. This circuit extracts the maximum power from a solar array to charge a battery stack. It employs the MAX856 boost converter and MAX982 dual comparator with reference. As a power source, the sun offers some....
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This really isn't much an electronics project as it is a telephone wiring project. Take note that this proejct involves connections to telephone lines. This may be frowned upon by your telephone service provider, AKA The Telephone Company. Always use proper....
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While they have been with us for many years, fluorescent lamps remain somewhat mysterious to most people. This isn`t really surprising, since their operation isn`t simple. The tube itself contains a mixture of gases, but the active ingredient is mercury.....
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For a hobby project I have bread boarded, I am considering using a pair detectors that operate as a single use physical barrier. When hit by a projectile, a trace is broken allowing +5VDC to to trigger a flipflop that is part of my gate logic for a....
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The ADUC812 MicroConverter is a fully integrated 12-bit data acquisition system-on-a-chip. Like all of ADI`s MicroConverter products, it features precision A/D & D/A conversion and a Flash Microcontroller on a single chip. ..
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Also known as the Free lamp (ie, online sellers, commonly known as Myanmar lamp), because it takes into ordinary household fixed telephone line voltage power to do, no batterie..
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The Infrared (IR) LED used in a remote control is an application for an LED Driver that has specific requirements that may exceed the requirements for a typical LED driver application. For this application, the IR LED driver will run off a 9V alkaline....
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Here is the particular schematic for the Tesla Coil that we will be building. I do not take credit for its creation - it was made by Steve Ward and yo....
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The power is all in the timed switching process. There are two main principles I use of switching the radiant energy the John Bedini way. First, the SG/SSG, Icehouse unidirectional circuit or John Bedini Monopole with the School Girl Circuit (SG)....
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The output of this circuit will be activated when a mix of two tone/frequency is detected on the input. The frequency f is determined by the values of R1 and....
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The calibrator operates on exactly 100 kHz providing a reference for calibrating the variable time base oscillator of general purpose scopes. For example, if the scope is set so that one cycle of the signal fills exactly 10 graticule divisions then each....
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As shown, OBO V20C as lightning protection module, lightning damage maximum current of 40kA; k relay; KM for the contactor; FU for the fuse; HL traffic lights. ..
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Function of the Two Siren Sound Circuit that is using IC 555. Siren Circuit is separated into three parts: low frequency production. The manufacturing shrill frequency and annex of production low frequency is obtained from IC1 connected to astable multi....
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The TV transmitter introduced here can send audio and video signals of satellite television receivers, VCDs and video recorders in open circuit, and receives signals with open antennas. It is suitable for self-made programs of working units, schools, and....
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These little devices had a 1. 5 inch 128x128 colour TFT as well as USB, batteries and 16 Mbytes of storage for around 140 pictures. Best of all they were very cheap, so I purchased a few to see if they could be re-purposed into something useful. Looking on....
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An ultrasonic, or sonar, range finder is a common sensor in robotic systems and industrial environments. Even home and automotive uses are possible. A novel sensor design consists of a WC, a few peripheral components, and a pair of ultrasonic transducers....
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This circuit is a 555 timer IC connected as a square-wave generator. Its base frequency is approximately 45kHz, as detennined by the values of Rl, R2, and Cl. The 45-kHz carrier is frequency modulated by a modified trapizoidal voltage waveform applied to....
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This circuit provides a precision voltage source that can be adjusted through zero to positive a..
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When ever I find an easy way to do something I just have to make a record of it. There are some projects where you might want to do something wireless with the Logochip. This little circuit makes it pretty easy. First an explination of the Radioshack....
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The simplicity of a traditional die makes it exceptionally difficult to create a fully equivalent electronic version, if only because an electronic version requires a power supply and a collection of electronic components that occupy a much larger volume....
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The amp has been designed to be an ideal upgrade for builders wishing to step up from Gainclones. This amp will kick out the power where Gainclones fall over, yet still maintain a sweet sound. The use of n-channel MOSFETs in the output makes the amp easy to....
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This is a single zone alarm - with independently adjustable Exit, Entry and Siren Cut-Off timers. It will accommodate the usual types of normally-closed input devices - such as magnetic-reed contacts, foil tape and PIRs. If you wish - you can use a mains....
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This section of code outlines the main sequence of operation for the sequencer. First, a for loop is utilized to govern which step the sequencer is operating in. Within this loop, first an address is made using the assignByteToPins() function, this sends a 4....
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Using a thermistor in the position shown makes a heat activated sensor. A change in temperature will alter the output of the opamp and energize the relay and light the LED. Swapping the position of the< thermistor and 47k resistor makes a cold or frost....
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The brake lights of the automobile trigger this circuit on and off. This save the annoyance of the alarm when it is not needed. This is an older circuit which was published in Popular Electronics Magazine, but still a good circuit today...
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This is a variation on the astable multivibrator. Circuit was recently developed to test for N-mosfets(the power kind e.g irf830)....
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The simple transistor tester in Figure 1 lets you identify the type of transistor, and it helps in detecting a transistor`s emitter, collector, and base....
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My door alarm is a small device which sounds an alarm whenever the door is opened. It is ideally used when you want privacy, if you want to know if other people enter your room while you’re in another part of the house, to wake you up if someone enters your....
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When the telephone rings the line voltage rises to 72 volts. At this time the LED in the opto-coupler glows and the transistor conducts. Due to this the transistor Q1 conducts. This makes the relay ON. The load connected to the relay whether bulb or bell....
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Sometimes amateurs like to home-brew their power supplies instead of purchasing one off the shelf at any of the major ham radio retail dealers. The advantage to rolling your own power supply is that it teaches us how they work and makes it easier to....
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This window generator uses a single LM324 op amp and features two adjustable set points. When the two comparators formed b..
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flip flop A bistable multivibrator. A circuit which has two output states and is switched from one to the other by means....
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This is A 8 bit Up/Down Counter that together with the “8 Bit Binary to 256 Decimal (1 of 256) Decoder “ makes a Run Light. I tried to to put all the 256....
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If an oscillator of a particular frequency and mark to space ratio is required, (see Fig. 4. 4. 1) the method would be to calculate periodic time from the required frequency and the discharge time and charge time using the formulae for tD and tC described in....
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The first part of the circuit here is a preamplifier consisting of transistor Q1(2N2222). The collector of the Q3 is coupled to the base of Q2 (2N2905A), which forms a complementary symmetry pair with Q3 (2N3053). The amplified signal is available at the....
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Using this low-cost project one can reproduce audio from TV without disturbing others. It does not use any wire connection between TV and Loud Speaker. In place of a pair of wires, it uses invisible infra-red light to transmit audio signals from TV to Loud....
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This dc voltage doubler circuit produces a voltage that is twice its voltage supply. This is useful when a higher voltage level is needed out of a single l...
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Here is a very simple and useful project of a moisture level LED Meter circuit that can be used as a sensor or detector to measure humidity or moisture level in plants, soil, wood, wall, floor etc....
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This tutorial explores a common digital concept using the NI Multisim software environment. It examines a four-bit counter that uses a 555 timer IC to generate the clock signal. This tutorial takes less than 30 minutes to complete and consists of 37 steps to....
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If you`ve dabbled with PIC18F microcontrollers and the USB Generic HID standard before (perhaps you`ve even tried my Building a PIC18F USB device project) then you will have noticed that there is a lot of complexity in supporting USB on both the PIC18F and....
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In order to achieve a status between two levels of switching for two calls at the same time, you must first establish privacy on each call. Otherwise, you will end up with all four phones talking to each other, and that just won't do. So the Link 'P' is an....
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The drive level of a crystal unit is shown by the level of the operating power or the current consumption (see Figures 9, 10, and 11). Operating the crystal unit at an excessive power level will result in the degradation of its characteristics, which may....
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The circuit of the transmitter is shown in Figure 1, and as you can see it is quite simple. The first stage is the oscillator, and is tuned with the variable capacitor. Select an unused frequency, and carefully adjust C3 until the background noise stops (you....
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A monolithic phase locked loop for data communications. The IC contains a basic phase locked loop for tracking an input signal within the pass band, a quadrature phase detector which provided carrier detector and an FSK voltage comparator which provides FSK....
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The monostable flip flop is a electronic circuits that is used to produce a single pulse each time it is triggered. Sometimes, this circuit called a `one...
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This TDA2030 35 watt audio amplifier circuit project is designed to provide an output power of 35 watts on to a 8 ohms load. The TDA2030 is a monolithic IC in Pentawatt package intended for use as low frequency class AB amplifier. The TDA2030 provides high....
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This transmitter can be tuned to the FM broadcast band, 2 meters,-or other VHF bands by changing C5 and Ll. The values given for C5 and Ll will place the frequency somewhere in the FM broadcast band. Ll is 4 turns of #20 enameled wire airwound, % inch in....
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Up to 100 lights, LEDs, or optocoupler triac circuits can be sequentially activated by this circuit. One (Ul) 4017 decode co..
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The temperature measuring range of this electronic thermometer is 0-50?, the precision is 0.1?, the measurement results are intuitively displayed by digital display. This electronic thermometer circuit is composed of temperature detection circuit, monostable....
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Many Video Operated Relay (VOR) circuits have been published in recent years for use in connection with ATV repeater controllers or automatic videotape logging systems. Unfortunately, many of these circuits fail to properly detect certain video signals....
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This is a simple NiCd battery charger powered by solar cells. A solar cell panel or an array of solar cells can charge a battery at more than 80 % efficiency provided the available voltage exceeds the fully charged` battery voltage by the drop across one....
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Regardless of whether you want to effectively imitate a house fire, a campfire, or light from welding, the circuit described here fills the bill without using a microcontroller, although it does use a larger number of components (including some truly....
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The recent tsunami in Japan and the on-going calamity with the Fukushima nuclear power plant has apparently greatly increased sales of radiation meters, n....
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This circuit uses a digital pot to allow the microcontoller to automatically adjust the gain of the circuit to suit the ambient audio volume, but you could replace this with a standard pot if this isn`t needed. The low pass filter is a copy of Graham....
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The phase shift oscillator of Figure above produces a sinewave output in the audio frequency range. Resistive feedback from the collector would be negative feedback due to 180o phasing (base to collector phase inversion). However, the three 60o RC phase....
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The following circuit shows about Noisy Regen Receiver Circuit Diagram. Features: used in model remote-control systems, 27-MHz superhet receiver ....
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This circuit is a circuit diagram of an indicator to show battery voltage 12 volts. Working principle of this circuit is the battery voltage compared with the reference voltage. By using the LM324 IC, which is a type LM324 Low Power Quad Operational....
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A very simple low cost water level indicator circuit can be designed using this schematic circuit. This water level indicator is based on a simple CMOS IC CD4066 and indicates the amount of water present in the overhead tank and also gives an alarm when the....
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Figure 1 shows a simplified schematic of a typical low-voltage halogen-lamp transformer without the protection circuits and EMI filter. Q1 and Q2 with C2 and C3 comprise a classic, half-bridge topology that works in self-oscillating mode. The circuit....
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Using a dual polariity power supply (+-5V works fine) will cure most clipping problems. You will have to check the data sheet for the correct pins to connect your voltages. ..
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Consumers of mobile wireless devices expect a workable, real-world balance of performance and battery life. This is particularly applicable in third-generation (3G) wireless designs, due to the fact that these devices will house more powerful and feature....
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The main part of this circuit Doorbell two timer NE555 ICs. When someone hit the switch S1 momentarily, the speaker emits a sound of the bell, if the time period of the monostable multivibrator built around IC1. When the switch S1 pressed, IC1 is enabled in....