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Old 06-09-2018, 09:40 PM   #1
goontron
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Default Need capacitor meter

I've seen all these chinese LCR jobs, but they don't go <6pF. I need less than 6pF. Preferably cheaper as im out a job (again....).
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Old 06-10-2018, 12:42 PM   #2
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Default Re: Need capacitor meter

What exactly are you measuring?

picofarads add up very fast from moving wires around so there's a lot of error there to begin with...
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Old 06-10-2018, 01:05 PM   #3
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Default Re: Need capacitor meter

^ RF caps.
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Old 06-10-2018, 06:21 PM   #4
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Default Re: Need capacitor meter

Well, yeah, RF, but are you actually measuring capacitors or are you measuring cable capacitance or something to that extent? -- because around the 3pf range, the capacitance is so low that people tend to take two pieces of wire and twist them together. This means inaccuracy is rampant and you'll need to somehow design without exact capacitances unless you're building the caps on silicon, and you're not using a capacitor meter on silicon...
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Old 06-10-2018, 07:19 PM   #5
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Default Re: Need capacitor meter

^ I've got a whole mess of ATC RF microwave capacitors that are unlabeled and i need to identify the ratings so i can finish building my 100W 70cm amp...
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Old 06-10-2018, 10:16 PM   #6
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Default Re: Need capacitor meter

Wasn't it, if none fit the bill, make your own?
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Old 06-18-2018, 08:48 AM   #7
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Default Re: Need capacitor meter

BTW if you just need a quick check of a small pile of caps you can use my Sencore LC53 since we're (relatively) close by. However my "probe" is pretty shitty as proven when I tried to measure the cap of my varactor diodes, reading goes everywhere when I touch it.

You could also look for a LC53 as well, they may be available cheap since it's so old. It's designed to measure down to 1pF and has a resolution of 0.1pF, though once again, the numbers are crappy especially when trying to hook up pF capacitors especially SMT - I suppose I really should have some sort of jig to test them as touching them will throw it off.
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Old 06-18-2018, 09:04 AM   #8
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Default Re: Need capacitor meter

i think the atmel based component testers go down to a fraction of a picofarad.
never tried it though.
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Old 06-18-2018, 11:59 AM   #9
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Default Re: Need capacitor meter

The ridiculous thing about my LC53 is that if I zero the leads, it will happily report negative capacitance... easily giving -0.2pF or even -10pF hahahaha...

Anyway it was more for measuring leakage (capacitors) and Q (inductors). Not just value. Too bad it doesn't test "Q" for capacitors (i.e. ESR or tan δ)
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