Re: LF501EM5F No Power, Chirping/Beeping Transformer
Measure the dcv between the two legs of the cap then double the value for the Voltage of the cap.
Ceramic cap common failure mode is shorted circuit.
The capacitance of the ceramic cap is affected by the applied Voltage (beside the temperature). So you must be careful as to what you choose to put in.
https://cdn.badcaps-static.com/pdfs/...1cafebd52c.pdf
http://www.murata.com/en-us/support/...mlcc/char/0005
https://ec.kemet.com/ceramic-capacit...tage-ask-fae-1
https://www.maximintegrated.com/en/a...ex.mvp/id/5527
From MAXIM notes:
'Note, first, that as the package size increases, the capacitance variation with applied DC voltage decreases, and substantially.
A second interesting point is that, within a package size and ceramic type, the voltage rating of the capacitors seems often to have no effect. I would have expected that using a 25V-rated capacitor at 12V would have less variation than a 16V-rated capacitor under the same bias. Looking at the traces for X5Rs in the 1206 package, we see that the 6.3V-rated part does indeed perform better than its siblings with higher voltage ratings. If we had looked over a broader range of capacitors, we would have found this behavior to be common. The sample set of capacitors that I was considering do not exhibit this behavior as much as the general population of ceramic capacitors.
A third observation is that, for the same package, the X7Rs always have better voltage sensitivity than X5Rs. I do not know if this holds true universally, but it did seem so in my investigation.
Using the data from this graph, Table 2 shows how much the X7R capacitances decreased with a 12V bias.'
Measure the dcv between the two legs of the cap then double the value for the Voltage of the cap.
Ceramic cap common failure mode is shorted circuit.
The capacitance of the ceramic cap is affected by the applied Voltage (beside the temperature). So you must be careful as to what you choose to put in.
https://cdn.badcaps-static.com/pdfs/...1cafebd52c.pdf
http://www.murata.com/en-us/support/...mlcc/char/0005
https://ec.kemet.com/ceramic-capacit...tage-ask-fae-1
https://www.maximintegrated.com/en/a...ex.mvp/id/5527
From MAXIM notes:
'Note, first, that as the package size increases, the capacitance variation with applied DC voltage decreases, and substantially.
A second interesting point is that, within a package size and ceramic type, the voltage rating of the capacitors seems often to have no effect. I would have expected that using a 25V-rated capacitor at 12V would have less variation than a 16V-rated capacitor under the same bias. Looking at the traces for X5Rs in the 1206 package, we see that the 6.3V-rated part does indeed perform better than its siblings with higher voltage ratings. If we had looked over a broader range of capacitors, we would have found this behavior to be common. The sample set of capacitors that I was considering do not exhibit this behavior as much as the general population of ceramic capacitors.
A third observation is that, for the same package, the X7Rs always have better voltage sensitivity than X5Rs. I do not know if this holds true universally, but it did seem so in my investigation.
Using the data from this graph, Table 2 shows how much the X7R capacitances decreased with a 12V bias.'
(Respectfully) 
.
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