Frequency of ESR measurements
"Leonard Caillouet" wrote in message
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wrote in message
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I have a question about ESR measurements.
I have been doing some reading about ESR and the literature indicates
it can be a strong function of frequency. In the design a SMPS I
assume the ESR of importance is at switching frequencies (at least
for the line side capacitor).
I have also noticed that often the measurement made in trouble
shooting are low frequency measurements (step function - looking at
the abrupt change in voltage).
Is the above accurate and if so when a cap goes bad do the low
frequency measurements catch the majority of the high frequency ESR
failures. Are there significant failure modes where a low frequency
ESR measurement would miss the higher frequency ESR failure?
Thanks Much,
Most of the ESR meters that I have seen test in the 50-200 kHz range.
This pretty much covers the switching frequencies of most power supplies,
at least in consumer equipment that I am familiar with.
Leonard
Exactly ditto.My Bob Parker meter works at around 100kHz, and I have never
had a problem with it picking up any (several per week) faulty caps.
Arfa
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