EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: Anson on July 26, 2013, 12:50:47 am
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I just got my Mastech MS5308 LCR Meter and I am a bit confused. From what I have read most ESR meters test using a 100khz signal to allow in-circuit testing of caps right? Well I ma trying to use this meter set on capacitance and esr mode at 100khz and I am getting nearly always OL. And sometimes getting a reading that is very low value even on higher value caps. If I change the test frequency to 100 or 120hz many times I get a reading of 3.3 to 3.6mf. I am not sure what is going on.
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Most LCR meters can't do in-circuit tests. The Mastech has a test voltage of 500mV peak to peak, which can cause false readings due to turning on transistors, most testers capable of in-circuit readings are around 100mV. Keep in mind none of the in-circuit meters are particularly accurate either.
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On 100khz test voltage is lower, you can check with the scope.
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Measuring capacitance in circuit is not going to be accurate. ESR is usually slightly better, since you're only looking at orders of magnitude increases in ESR.
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Ok makes sense. So in circuit testing I should only pay attention too the ESR reading. Should I always test in circuit at 100khz?
Also a few other silly questions. When would you use DCR? What is wastage factor or D? And what is quality factor or Q? I guess I'll ask about phase angle also when does that come into play?
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Download the Agilent impedance measurement handbook (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&frm=1&source=web&cd=1&cad=rja&ved=0CDIQFjAA&url=http%3A%2F%2Fliterature.agilent.com%2Flitweb%2Fpdf%2F5950-3000.pdf&ei=nZzyUcbbD46A9QS63IDwBQ&usg=AFQjCNFqDakbj04lqosJbP_mATyL6VBUTw&sig2=rv12sfJnzHexz2XfdxW-ww&bvm=bv.49784469,d.eWU) don't worry about getting all the math just try to get the basics from it.
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Thanks! Just what I was looking for. :-+