build Measure capacitances

Thread Starter

pini200

Joined Feb 15, 2016
14
hello
I need to build device that Measure capacitances
the range of capacitance is 50nF-300nF
What's the best way to achieve accuracy
(I think use in 555 and how i build this )
thanks


 

AnalogKid

Joined Aug 1, 2013
8,251
There are many ways to do this. Three examples:
You can apply a calibrated DC voltage or current step and measure the rise time of an R-C network.
You can put the capacitor in an oscillator circuit and measure the frequency.
You can apply a sinewave through a resistor and measure the attenuation caused by the capacitor.

ak
 

wayneh

Joined Sep 9, 2010
16,155
A 555 circuit can be used, but you need to think about what precision and accuracy you need. (These are not the same - consider both.) A 555 is not nearly as precise as a crystal oscillator and will limit the quality of your results. Depending on what you are doing, it may be fine.
 
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