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GMB · 17th May 2021, 2:46 pm

I think using 50Hz is a mistake as it means your circuit must be totally screened from any mains influences. It is also not the best frequency for measuring inductance as typical impedances will be a bit on the low side. Most bridges would use a higher frequency for mH ranges.

I would dump the mains and have a battery powered oscillator to energise it.

The ideal null detector is an amplifier and magic eye. Second choice is amplifier with AGC and a meter - giving a very non-linear response. If you can add a phase detector to show which way to go then that is even better.

17th May 2021, 2:46 pm	#12
GMB Dekatron Join Date: Aug 2003 Location: near Reading (and sometimes Torquay) Posts: 3,100	Re: DIY Inductance bridge I think using 50Hz is a mistake as it means your circuit must be totally screened from any mains influences. It is also not the best frequency for measuring inductance as typical impedances will be a bit on the low side. Most bridges would use a higher frequency for mH ranges. I would dump the mains and have a battery powered oscillator to energise it. The ideal null detector is an amplifier and magic eye. Second choice is amplifier with AGC and a meter - giving a very non-linear response. If you can add a phase detector to show which way to go then that is even better.