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有没有测量原理介绍?有空时想设计一个来玩,
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有
the design presented here works by applying a 50khz, 200mv square wave to the capacitor under test, in series with a 10 ohm resistor. the ac voltage appearing across that resistor is measured and displayed on a meter. so the whole thing is nothing else than a simple ohmmeter that uses ultrasonic ac for measurement instead of the usual dc used by every common ohmmeter. since the ac voltage used is so low, it does not make semiconductor junctions enter conduction, which further helps to make this meter suitable for checking capacitors mounted in a circuit.
