06-05-2024, 04:33 PM
There are not enough parts to warrant a PCB, also you are doing only one.
Since the HT is measured, the lack of regulation may not matter. The heater voltage must be accurate as that affects the readings a lot, hence some AVO testers had a load of taps on mains to fine tune.
No need for optocouplers. I've repaired a few testers (3 x AVO, Hickock, another) and built a curve tracer kit. A simple valve tester simply has loads of switches. Some use unsmoothed half wave HT as the calibrated metering is adjusted to suit.V
Since the HT is measured, the lack of regulation may not matter. The heater voltage must be accurate as that affects the readings a lot, hence some AVO testers had a load of taps on mains to fine tune.
No need for optocouplers. I've repaired a few testers (3 x AVO, Hickock, another) and built a curve tracer kit. A simple valve tester simply has loads of switches. Some use unsmoothed half wave HT as the calibrated metering is adjusted to suit.V
