26-07-2016, 01:00 PM
Forgot to add that you can get a rough idea of the capacitance by discharging the cap through a resistor and seeing how long the voltage takes to fall. For a time constant C * R it will fall to 37% (1/e) of the original voltage in C * R seconds. Any leakage will discharge it faster. It will be close to zero volts in 5 * C * R. So a 100k resistor will give a 1.6 second time constant. you'll know pretty quickly if it's anywhere near its correct value.
ESR matters in switchmode power supplies and many other applications but for the smoothers in a old radio if the capacity and leakage are OK it's unlikely that ESR will bother you.
ESR matters in switchmode power supplies and many other applications but for the smoothers in a old radio if the capacity and leakage are OK it's unlikely that ESR will bother you.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
