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Schematic for capacimeter project

R

Rich Grise

Dear Sirs

I need a project for capacimeter in analog way.

Go to the other side of google, and type "capacitance meter" into the
search box.

Good Luck!
Rich
 
D

D from BC

Dear Sirs

I need a project for capacimeter in analog way.

I have an interest in this area to to measure anodized layer
thickness.
Guessing at Techniques.....
1) RC voltage divider driven by an audio oscillator.
2) Ctest is part of an LC oscillator, phase shift or hysteresis
oscillator.
3) Constant Iout. Time is measured to determine Ctest.
4) C measurement chip??
5) Maybe some method of phase measurement

I'd probably go for the voltage divider technique..
D from BC
 
W

whit3rd

I need a project for capacimeter in analog way.

Well, there's lots of ways to do that. Simple way #1, just
connect line current (this presumes constant power voltage)
to one side of the capacitor, and rectify the current through
the capacitor and run it through a moving-needle meter movement.

This only requires two diodes, a meter, and a known AC source.
Downside: high voltages blow up some capacitors, and other
capacitors will blow up your meter movement. Also, don't
touch it with the power on!

Better solutions require other (safer) AC sources, and use
amplifiers with range settings.

For practical purposes, digital C-meters are easy to build; it turns
out
that the usual voltmeter (dual-slope converter) operates in two
phases,
first charging a capacitor with an unknown, then timing the
discharge with an accurate known discharge current source.
If you give the capacitor a known voltage in the first phase, the
discharge time (and thus the digital readout) is proportional
to the capacitor value.
 
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