Electronic – transformer has continuity but no voltage output

power supplytransformertroubleshootingvoltage

I have two old transformers that appear to be fine, however no DC voltage was measured on the secondary coil.

I have measured:

The input voltage: 229 AC
the input coil ohms: 0.015 kOhms
the two parallel output coil ohms: 0.008 kOhms each
the multimeter base resistance when i touch the probes = 0.006 kOhms
resistance between AC and DC coils – no continuity.

The other transformer is similar, continuity between the primary and secondary, AC 230 in, DC 0 out.

What kind of problem affects both these transformers?

Best Answer

If they are transfomers rather than DC power supplies, then you would measure zero volts DC at the output even though the transformer is working correctly.

A DC voltmeter will show zero volts when measuring AC.

Switch the multimeter to AC volts to measure the transformer output.