09-05-2019, 03:10 PM
(This post was last modified: 09-05-2019, 03:13 PM by John Cornforth.)
Hi JonE
The capacitance value you would expect will be between 0.25 uF (microfarads) and 0.4 uF. This is the same as 250 nF (nanofarads) to 400 nF. Most meters change range automatically, if not set the maximum scale to something like 1 or 2 uF.
The polarity of the test leads will not matter.
You will only get a valid test if the coil is disconnected and the points are open, so that you are measuring the condenser alone and not other things hanging off it.
Having said all this, a measurement with this sort of meter (which works at a fairly low signal level) may show the capacitance value to be OK but the capacitor can still be faulty. For example it may have high/intermittent internal series resistance or leakage or breakdown under high voltage conditions. So it's a start - but not a conclusive test.
Cheers, John Cornforth
The capacitance value you would expect will be between 0.25 uF (microfarads) and 0.4 uF. This is the same as 250 nF (nanofarads) to 400 nF. Most meters change range automatically, if not set the maximum scale to something like 1 or 2 uF.
The polarity of the test leads will not matter.
You will only get a valid test if the coil is disconnected and the points are open, so that you are measuring the condenser alone and not other things hanging off it.
Having said all this, a measurement with this sort of meter (which works at a fairly low signal level) may show the capacitance value to be OK but the capacitor can still be faulty. For example it may have high/intermittent internal series resistance or leakage or breakdown under high voltage conditions. So it's a start - but not a conclusive test.
Cheers, John Cornforth