Ceramic chip capacitors voltage dependance.

[David_]

Hello.

I know about the voltage dependance of the capacitance of a MLCC ceramic capacitor, but how does that impact the value if I put two 50V 10µF in series across a 50V rail as opposed to one 100V 10µF across that same 50V rail?

Regards

 

[jiripolivka]

Hello.

I know about the voltage dependance of the capacitance of a MLCC ceramic capacitor, but how does that impact the value if I put two 50V 10µF in series across a 50V rail as opposed to one 100V 10µF across that same 50V rail?

Regards

I doubt a 10 uF capacitor is a "ceramic" one. It is rather an electrolytic capacitor. Connecting two in series is not safe unless you connect to each one a parallel resistor , 10 - 100 kOhm.

Using 100 V rated capacitor on a 50 V DC line is much safer.

 

[FvM]

Presume you know that two 10 µF in series gives 5 µF total capacitance.

Resistors to guarantee equal voltage sharing are suggested for a DC operated series circuit.

Both capacitor alternatives are operated at 50 percent of rated voltage, but voltage dependency can be different, you'll review the indivual data sheets to know which performs better.

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I doubt a 10 uF capacitor is a "ceramic" one.

10 µF/100 V ceramic is definitely available from major manufacturers, X7R or X7S, 1812 or 2220 size.

 

[David_]

Okey, yes I should have thought about two 10uF caps equals 5uF.
But what spawned this question is that I can find 1 4,7uF 100V cermaic cap at 1/5 the cost of a 10uF 100V cap and I thought maybe I can make the 4,7uF worth while.