Popular Circuits Page 121
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An awful thing happened a few weeks ago. I ran out of telephones to restore. All my payphone projects were finished. They were lined up on shelves doing what antique telephones do best - collect dust. I also wanted to write about a special project for the....
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There are numerous posts on Instructables about how to make a flickering LED candle. This is my version. The project requires the following components...
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This circuit is similar to the one above but uses positive feedback to get a little more amplitude to the speaker. I copied it from a small 5 transistor radio that uses a 25 ohm speaker. In the circuit above, the load resistor for the driver transistor is....
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This is a programmable clock timer circuit that uses individual LEDs to indicate hours and minutes. 12 LEDs can be arranged in a circle to represent the 12 hours of a clock face and an additional 12 LEDs can be arranged in an outer circle to indicate 5....
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Fluorescent dimming systems can satisfy visual comfort, and reduce utility costs through daylight harvesting, demand reduction, scheduled dimming, and other strategies. A dimming electronic ballast is an essential part of this system. To perform dimming....
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Sometimes you have a situation where you have a 5-V supply voltage but part of the circuit needs a lower supply voltage. A voltage regulator from the Texas Instruments TPS62000 family [1] is a good choice for this if the current consumption is less than 600....
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Wien Bridge Oscillator Tutorial about the Wien Bridge Oscillator Circuit which uses a RC Phase Shift Oscillator to produce sine waves....
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2W resistors can be used around a metal or carbon film resistors fortunate optional paper referred capacitors, polypropylene capacitors, voltage of 400V on the nozzle; capacito..
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Notes: LM3909, Capacitor, and LED are Installed in a White Translucent Cap on the Flashlight"s Back End. Only One Contact Strip (in Addition to the Case Connection) is Needed for Flasher Power..
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A DTMF-based IR transmitter and receiver pair can be used to realize a proximity detector. The circuit presented here enables you to detect any object capable of reflecting the IR beam and moving in front of the IR LED photo-detector pair up to a distance of....
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The analog input is fed into the span resistor of a DAC. The analog input voltage range is selectable in the same way as the output voltage range of the DAC. The net current flow through the ladder termination resistance; i.e., 2 KO for HI-562A; produces....
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This circuit is intended for children fun, and is suitable to be installed on bicycles, battery powered cars and motorcycles, but also in models and other games. With SW1 positioned as shown in the circuit diagram it reproduces the typical dual tone sound of....
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The requirements for electric energy quality of modern industrial development are higher and higher, how to offer the safe and reliable green power to energy consumer is a focus of area research of the power at present. UPS, as a kind of incessant power....
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A valve radio receiver in its crudest form is a frequency determining tuned circuit, (consisting of an inductor and capacitor in parallel) followed by a series of valves coupled together. These valves act on the signal and provide high frequency....
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This is an image Schematic. No Description available...
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Plasma Globes were invented by Nikola Tesla some time before 1892. Glass-enclosed Tesla coil terminals containing low-pressure gases were part of his effort to develop a new source of lighting not covered by the Edison patents. The same device became an art....
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The circuit provided right here allows up to eight participants with each one assigned a unique number (1 to 8). The display will show the number of the Electronic jam circuit diagram. contestant pushing his button prior to the others. Concurrently, a buzzer....
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Transformer T1 supplies power to the heater of the sensor. Since the sensor is fairly sensitive to heater voltage, diodes Da, D4, and D5 regulate the heater voltage. Tl, together with D1 and CZ, forms a de power supply, whose current is regulated by Q1 and....
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Here is a circuit for using the printer port of a PC, for control application using software and some interface hardware. The interface circuit along with the given software can be used with the printer port of any PC for controlling up to eight equipment .....
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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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Below is automatically converted to low-voltage circuit. 220V electricity through step-down transformer T after, VDw breakdown camel guide so VT1, VT2 off, solid state relays S..
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Circuit shown in Figure 3-191. The line in the DC motor armature circuit in series two-stage startup resistor Ri, Rz, Lee realized using the buttons to start and stop the motor..
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Using 555 lights lighting group delay IC circuit of the circuit shown in Figure 2-46. By the 555 IC and resistor-capacitor circuit composed of the delay. The circuit without light transformer T is still energized, energy. Delay time is determined by Ri, C2...
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This is a very simple liquid detector that use a relay to open an evacuation van. You can use it for water or any liquid that conduct electricity. Use any PNP transistor that can stand the relay current. Check out the new water level sensor circuit...
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The electromagnetic ring launcher is comprised of four subcircuits: a clock circuit (built around U5, a 555 oscillator/timer configured for astable operation), a count-down/display circuit (built around U3), a 74190 synchronous up/down counter with BCD....
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This audio amplifier circuit, connected to 32 Ohm impedance mini-earphones, can detect very remote sounds. Useful for theatre, cinema and lecture goers: every word will be clearly heard. You can also listen to your television set at a very low volume,....
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This 2-band compressor splits the audio into high and low frequencies and allows independent adjustmen..
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The circuit shown in Fig. 62-15A is designed to drive a 15-V, two-phase, bipolar stepping motor, providing a bidirectional single level voltage across each winding at currents of up to 9.6 A. The circuit consists of two identical transistor bridge stages....
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This following circuit shows anpower supply wiring diagram for Nissan 300ZX, sport car called as Fairlady Z. Component: lighting switch,ECCS, fuse ....
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I have found the schematic diagram on Metal Detector For this class it does not have to be orginal, the project can be taken from the internet. I have a few questions regarding this schematic diagram. There is a small arrow connected from the Emitter of the....
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3-9V adjustable lOOmA power supply as shown in Figure 12-30 power supply, there is a series regulator circuit using the amplifier tubes, the output voltage from the 3 ~ 9V cont..
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The transition from diodes to synchronous-rectification (SR) MOSFETs in secondary circuits of flyback converters increases with each new generation of MOSFETs, improving performance at little or no cost penalty. SR MOSFETs can be more efficient than diodes,....
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Firecrackers are normally ignited by using a matchstick or a candle. You have to run away quickly after igniting the fuse of the firecracker. This method of igniting firecracker is unsafe, because the danger of the firecracker bursting before you reach a....
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The iron intelligent control circuit shown. In this circuit, the integrated circuit PT8A351X, irons by placing direction detection identification switch, relay and LED control, when the iron horizontally, @ feet high, iron after..
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With the storm season recently upon us, it`s not uncommon to switch car headlights on during the daytime. Unfortunately, it`s easy to forget to turn them off again when parking, with the result being a flat battery. This circuit will sound an alarm if the....
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Circuit shown in Figure 3-132. The line is automatically round-trip, plug braking circuit. In order to prevent or limit switch SQl offside SQz malfunction caused the accident, ..
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This is a DC to AC inverter using 555 timer and a transformer that is 9-0-9V/230V and rated at 36VA. Component: 555 IC, TIP42C and TIP41C ....
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The following document will provide information to develop your own VACI (Vehicle Accessory Computer Interface). What I have done is rather simple, however it took about 3 weeks of planning, programming and debugging. The wow factor on this interface is....
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This is a fairly simple project for anyone with some electronic skills. Plug this circuit into an audio source and the LEDs will blink to the rhythm o....
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The usual method for using a current-feedback amplifier to drive a capacitive load isolates the loa..
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This device was designed to replace the original digital clock in a Fiat Ducato 1992-1994, mounted just above the inside rearview mirror. The original clock is not very accurate, only displays time and is sensitive to interference (e. g. from Xenon....
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However, for applications needing many LEDs, this becomes extravagantly inefficient and it is tempting to keep the voltage drop across the resistor as small as possible. That leads to poor control of the current. ICs such as the MM5450 and its relatives and....
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The Intersil ICL7106 and ICL7107 are high performance, low power, 31/2 digit A/D converters. Included are seven segment decoders, display drivers, a reference, and a clock. The ICL7106 is designed to interface with a liquid crystal display (LCD) and includes....
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This circuit uses an LED and 4081 CMOS integrated circuit. The variable resistor sets the voltage at which the LED turns on. Set the control so that the LED lights when the voltage from the car"s ignition switch drops below 13 volts..
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This 5-V circuit utilizes a servo-controlled dc/dc converter to generate the compliance voltage necessary for loop-..
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Below it is a circuit of power amplifiers with power output of 450 watts mono, amplifiers are also frequently used in the amplifier a high-power amplifier, which used in an event, in the field and the placed closed. Because this amplifier suitable for the....
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Can be directly connected to CD players, tuners and tape recorders. Tested with several headphone models of different impedance: 32, 100, 245, 300, 600 & 2000 Ohm.
Schematic shows left channel only...
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The circuit is built around the IR2520D Ballast Control IC. The IR2520D provides adjustable preheat time,
adjustable run frequency to set the lamp power, high starting frequency for soft start and to avoid lamp flash,
fault protection for open filament....
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Itis often required that a signal be filtered prior to sampling. This can be accomplished with only one device. Use any of the inverting and noninverting filters that can be built with op amps. ..
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Most switch-mode power supplies rely on a PWM (pulse-width-modulated) output that is controlled via voltage feedback. A 555-timer IC can inexpensively perform PWM. The circuit in Figure 1 shows how to turn a 555 PWM circuit into an switch-mode power supply....
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This chapter contains circuit diagrams for several power supplies for pulsed solid state lasers. These include units suitable for driving the popular Hughes ruby and YAG rangefinder laser assemblies as well, one using the flash from a disposable pocket....
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Ethernet has traditionally been a quite complex interface. All Ethernet chips until today had 100 pins or more, where difficult to find in small quantities and difficult to use from a small microcontroller with little memory. Microchip has changed the world....
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This op-amp analyzer can measure the current drawn by any device in a car. The analyzer works by measuring the very small voltage that develops across the battery cables when current flows..
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The preamplifier is protected from excessive input signals of either polarity by the 2N5909 junction field-effect transistor. A nulling circuit makes it possible to set the preamplifier output voltage to zero at a fixed low level (up to + 10~8A) of the input....
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This design will interest technicians who work on pneumatically operated valves and other 4-20mA current loop controlled devices. Although 4-20mA signal injector/calibrators are available, this one is both cheap to build and easy to operate. When first....
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The ELC presented here has some flexibility, thanks to being software-controlled, but also has its limitations: It's intended for microhydro systems that employ a single-phase synchronous alternator, working at 220-240V, 50Hz, in a power range up to 25....
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The measured resistance of door lock motor was about 2 ohm. Therefore, supplying 5V, the current becomes 5v/2ohm= 2. 5A. Regarding that the peak output current of L293B is 2A, the current flowing inside the motor is slightly over 2A, but it does not occur....
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The following circuit shows about Simple Battery Charger With The Temperature Sensor. This circuit based on the LM350 IC. Features: negative ....
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This oscillator circuit permits crystals to be electronically switched by logic commands. The circuit is best understood by initially ignoring all crystals. Furthermore, assume that all diodes are shorts and their associated 1kO resistors open. The two 1kO....
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An ultra low noise audio preamplifier particularly suited to microphone preamplification including balanced microphones. The IC features wide bandwidth, low distortion only 0.007% at a gain of 100, ..
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Adjustable Gain Test in preparation isolation amplifier circuit as shown below, the use of optical coupling isolation amplifier ISO100, adjustable gain can be composed tone tes..
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This was a small circuit made for driving an Impact counter. The heart being ICL8038. It must have been a Motor driving a Conveyor, the motor has a feedback attachment called Tachogenerator. Only part of the circuit is shown here. See the image of product....
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This simple mobile voltage regulator circuit may save your two meter or CB transceiver if the voltage regulator fails. The 2N3055 should be heat sinked if current drawn by the rig is in excess of 2 A on transmit..
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Circuit diagram is one of the circuit diagram to set the tone. Circuit diagram This is controlled by using the tone control IC TDA 1524 the type that includes all of the balance of bass and treble volume in one IC TDA 1524 a. You can setting a potentiometer,....
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The circuit depicted here forms one half of a device that will prove extremely handy when tracing the path of electrical wiring in a building or to locate a break in a wire. The system is based on similar equipment that is used by technicians in telephone....
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This is the schematic for an FM transmitter with 3 to 3. 5 W output power that can be used between 90 and 110 MHz. Although the stability isn`t so bad, a PLL can be used on this circuit. This is a circuit that I`ve build a few years ago for a friend, who....
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This circuit is a voltage-controlled oscillator, which is an oscillator whose frequency is determined by a control voltage. A 10 Hz sawtooth oscillator provides the control voltage in this case; this causes the frequency to rise slowly until it hits a....
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This is the Snap Circuits Motor Control IC, or H-bridge. At the top of the figure you can see the electronic schematic of the Motor Control block. On....
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Communication with the MCP3028 ADC chip is done using a simple serial interface compatible with the SPI protocol. The Pic16f84 or Pic16f628 didn`t had hardware SPI peripheral. However, software implemeted SPI protocol can be done to communicate with 12 bit....
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TC9402 The TC9400 TC9401 TC9402 are low-cost Voltage-to-Fre- quency (V/F) converters, utilizing low-power CMOS technology. The converters accept a variable Analog input signal and generate an output pulse train, whose frequency is linearly proportional to....
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The power amplifier circuit using MOSFET has been very popular, because the sound is very aggressive, as compared to transistors and ICs. It can be low-frequency and high-frequency response as well, it is highly durable. Usually, if compared with the same....
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Here`s how to build your own adjustable power supply based on LM317. The IC LM317 is so versatile that an almost unlimited number of different, small, high grade power supply circuits can be built using it. The configurations can be introduced for different....
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The whole system was built in a package that was about 70mm x 96mm x 30mm which contained the TNC, transmitter, interface circuitry and a lithium battery sufficient for about 20hours of continuos operation. All in weight (including battery and antenna) was....
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Neon lamps serve as diode gates and indicate positions and moves on game board. Thyratron-relay com bination serves as memory, while relays referee sequence to prevent two successive moves by either player. -C. E. Hendrix and R. B. Purcell, Neon Lamp Logic....
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This is a simple PWM modulator circuit. Comparing the message signal to a ramp or triangular waveform is the simplest way to produce a PWM signal. When the....
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One yet circuit with the known LM3915. It does not differ in a lot of points from other applications with same IC. The circuit accosted in those who they want a Vumeter that will be connected in the exit of power amplifier. It can be adapted his sensitivity....
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The battery charger circuit below is very simple to build requiring only a handful of cheap parts and an extra winding on your power tranny (or a separate tranny). Since the charger described is not active during sound reproduction, I have made no criteria....
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This circuit features automatic Exit and Entry delays and a timed Bell Cut-off. It has provision for both normally-closed and normally-open contacts, and a 24-hour Personal Attack/Tamper zone. By using the Expansion Modules, you can add as many zones as you....
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The power supply is just a 7812 voltage regulator followed by an op-amp set to 6V to create a half way supply voltage for the audio op-amp stages. A 12V regulator seems to be too high for a battery fed application. These 4 outputs are all followed by a....
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Most all power supplies regulate either their output voltage or output current at a constant level, depending on the load resistance relative to the power supply`s output voltage and current settings. This can be summarized as follows: To accomplish this....