Free electronic circuit design and schematic diagram
This schematic diagram shows a circuit of basic logic gate circuit. This PNP transistor circuit can act as OR gate or AND gate. If the input is closing of switch, this circuit acts as AND gate. This circuit acts as OR gate when the input is opening of switch. The phase inversion of input does not complicate overall circuitry. Here […]
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Relays are normally operated at current level where it can initiate the mechanical metal contactors movement. After contacts has been established, the current level needed to keep the conductor plates stay attached is actually smaller than the current to initiate it. This power saver circuit seems to have opposite mechanism of surge protector. This circuit provide surge current to initiate […]
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This doorbell circuit produces a low tone that will slide up to higher frequency. The equivalent total resistance connected between the base of Q1 and ground (Rbg) , and coupling capacitor C1 determines the AF oscillator’s frequency. The resistance (Rbg) is equal to (R2+R1)R3. Here is the schematic diagram of the circuit: The R2 is used to set the initial […]
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This true stereo indicator is different from what we usually find on FM radio receiver, which is usually a pilot tone detector. A stereo broadcast from FM radio station contain pilot tone, but a presence of pilot tone doesn’t necessarily a stereo broadcast signal since a mono FM transmitter ca broadcast pilot tone as well. Since this circuit detect the […]
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This is a one direction motion sensor circuit. This motion sensor circuit is used to detects an object passing in one direction, ignoring an object that going to opposite way. This circuit uses two sensors to identify the movement only in one direction. The basic principle of this circuit is simple, where one sensor is used to generate a short […]
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A schematic diagram of simple tachometer circuit is shown below. Using only a single transistor as the active component, this tachometer would probably be the simplest one. The input of this circuit can be picked up from ignition pickup coil, or other wiring that gives ignition wave-form. This tachometer circuit works for 0 to 6,000 rpm. R3 is used for […]
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This voltage regulator circuit operates in switch mode. Using the configuration shown in the schematic diagram, this circuit has variable switching frequency, depends on the input voltage and load condition. The core controller of this switching regulator is a TL497 switching regulator controller IC. Here is the schematic diagram of the circuit: When the load is low (draw only small […]
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