Overpotential Capacitor Usage in a DC-Dc Transformer

Discussion in 'General Electronics Chat' started by kcarring, Jan 26, 2011.

  1. kcarring

    Thread Starter Member

    Jan 22, 2011
    Overpotential Capacitor Usage

    If I have a circuit (and I don't, sorry...) - so in general - if placing a capacitor over both leads to the primary on a dc-dc transformer coil - when that circuit say, calls for a 10v 10,000 uF Electrolytic Capacitor, and instead I use a much larger 80v 15,000 uF Electrolytic capacitor - what effect in general does that have on the transformer?

  2. tom66

    Senior Member

    May 9, 2009
    The increase in voltage rating should not have a significant effect but we would need to see the circuit to attempt to determine if the increase in capacitance would affect it.
  3. SgtWookie


    Jul 17, 2007
    Well actually, the higher voltage specification means that the capacitor is physically much larger, and will almost certainly have a higher ESR (equivalent series resistance) than the 10v capacitor. If the converter is running at a high frequency, this may result in excessive heating of the capacitor due to the higher parasitics, and lower output power from the transformer. Adding a smaller cap in parallel may help.
  4. Jaguarjoe

    Active Member

    Apr 7, 2010
    Using an electrolytic capacitor at a voltage much lower than it is rated for can cause the oxide layer to "deform", just like when a cap sits in a box for a very long time.
    Last edited: Jan 26, 2011