Free Simple Circuit Diagram
This is a voltmeter circuit that use FET as the buffer to improve the input impedance. This circuit uses A2N3819 FET which provides a solid-state VOM. Beside that, a cathode follower in a VOM of this circuit is The 2N3819. The calibration of this circuit is done by adjusting R12 (scale/sensitivity) and R14 (zero offset). Since FET has very high […]
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This is a Peak Voltmeter circuit. This circuit can be viewed as a pulse stretcher, which catch fast pulse signal to be measured by a slow response voltmeter. Even a fast response meter need this circuit since our visual perception won’t be able to catch a fast event. Here is the schematic diagram of the circuit: This circuit is used […]
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Analog meter normally doesn’t have high impedance since they don’t have buffer circuit inside. With active buffering, the input impedance of this circuit depends on the impedance of the op-amp. You can use other op-amp for higher impedance, but a low-cost 741 is enough for may application. The rectification inside the feedback loop path remove the effect of diode’s voltage […]
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Below is a comparator circuit which is can measure with step of 1 volt, the voltage of car battery. The indication of voltage is done by comparison of battery voltage with the reference set by D1. This voltage is applied to the inverting inputs of amplifiers with to compare the battery voltage. We can regulate the gradation of voltage that […]
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