For example, I need 100uF 60V capacitor for filtering in power supply. The DC source is about 40V, but I have 400uF 20V capacitors.
If I arrange four of them in series I got in total 100 uF and each capacitor has a voltage drop of 10 volts according DC source.
Thus, can I replace 100uF 60V capacitors with four 400uF 20V capacitors in series? Are 20V capacitors OK?
How can I design symmetrizing resistors for it?
Best Answer
You will have to include a parallel resistor-ladder to stabilize the node voltages. The resistor values must be high enough for the low-pass to be effective $$f_c = \frac{1}{2\pi RC} $$ and low enough to ensure a save operating point (smaller than the capacitors leakage). This will cost you some additional power.