[Ronja] Measuring capacitance of inductors with Twister

[Gyurkó Martin]

Careful!

1x usually is a normal koax cable
10x is something weird with the capacitance, and it is not so easy to 
say, especially when you adjust the probe with it's trimmer.
I would guess it is the input cap.

Direct using of 50 Ohm cable?
would it destroy the measurement results?

Martin

Karel Kulhavy írta:
> I needed to measure the self-capacitance of a small coil (2.8-20 uH). I Connected
> U60-13 in Twister over a 8k2 resistor to the coil and the other side to ground. Then I
> put oscilloscope trigger on U60-13 and oscilloscope input to the coil. I have read out
> the ringing frequency (coil resonant frequency) and from the known inductance (I have an inductance meter) I have calculated the capacity which ranged from 12 to 14 pF :)
> 
> The scope probe says "8.0pF" but doesn't say if it's the input or output capacitance, i. e. if I have to divide by 10 and the real input capacitance is 0.8pF. Anyone has an idea?
> 
> KArel
>