I recently purchased a cheap chinese benchtop digital scope. I wanted to use it to measure inductance, by making an LC circuit and seeing the damped oscillations, measuring the distance of the period of the wave(aka the frequency).
I used the following formula: 1/sqr(2pi*f)*C, where C is a known capacitor. My setup consisted of me charging a capacitor, and then plugging in it in the LC configuration, I set my scope for single shot capture, I measured the resulting waveform, but according to the formula, it puts the inductor in the order of femtohenries. The inductor is a hand-made coil with several turns of a UTP cable, whose diameter is around 0.52mm. It should have been several hundred nanohenries, so I then used a known 100 microhenry inductor(the type with 4 color code bands), and a 1000 microfarad(electrolytic) capacitor, but the resulting frequency, was around 1.5mhz, rather than the 0.0005033mhz that it should have been. I also tried using a 1 microfarad film capacitor, but the frequency was still wrong..
Perhaps I've hooked it up wrong? I place the oscilloscope probe on one end, and the ground probe to the other end of the circuit.
The scope is not the best, it is a Hantek DSO5102P, 100Mhz BW(says 1Gsa/s) but with a rather small memory of 40 kilopoints.
I used the following formula: 1/sqr(2pi*f)*C, where C is a known capacitor. My setup consisted of me charging a capacitor, and then plugging in it in the LC configuration, I set my scope for single shot capture, I measured the resulting waveform, but according to the formula, it puts the inductor in the order of femtohenries. The inductor is a hand-made coil with several turns of a UTP cable, whose diameter is around 0.52mm. It should have been several hundred nanohenries, so I then used a known 100 microhenry inductor(the type with 4 color code bands), and a 1000 microfarad(electrolytic) capacitor, but the resulting frequency, was around 1.5mhz, rather than the 0.0005033mhz that it should have been. I also tried using a 1 microfarad film capacitor, but the frequency was still wrong..
Perhaps I've hooked it up wrong? I place the oscilloscope probe on one end, and the ground probe to the other end of the circuit.
The scope is not the best, it is a Hantek DSO5102P, 100Mhz BW(says 1Gsa/s) but with a rather small memory of 40 kilopoints.
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