Author Topic: LCR meter  (Read 1689 times)

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Offline z3bb0

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LCR meter
« on: June 29, 2015, 08:51:24 pm »
So I'm trying to build something a little more advanced than what I've built before and I've decided that I want to build an LCR meter. In terms of performance I'm thinking measuring capacitance down to 1pF, inductance down to 1nH and dc resistance as well as ESR down to 1mOhm and by down to I mean that 1mOhm is the least signifigant digit, measuring frequency 10Hz - 100KHz. So what I think I will do is have a dac output the signal though the DUT, and measure the current and voltage across the DUT. Nearly exacly how the HP4263A works, see video at 11:23, but with out the vector ratio detector. What I want help with is what kind of sample rate and resolution is required for both the DAC and ADC.
I've stumbled across this part and figure it might be enough, but since I really have no idea what I'm doing... This is the chip I'm figuring might work as the ADC: AD9201 10bit, 20Msa/s, 2 channels one for current and one for voltage allowing me to measure the phase and thus get ESR and reactance in one measurement. Is 10 bit really enough though? or should I do something like having a 1 channel ADC and measuring the impedance at 2 different frequencies say 95 and 105 Khz and then solving for the ESR. And lastly if I where to use the AD9201 or what ever you suggest, what kind of microcontroller is needed to use the ADC control the DAC and control some kind of low res display or possible four 14segment displays or something similar, to clearify: what kind of power is needed I don't want to use some expensive ARM chip where the programming tool costs 500$. Thanks for the help in advance! :-+

« Last Edit: June 29, 2015, 09:37:09 pm by z3bb0 »

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