Re: Issue with homemade diode power sensor for HP meters
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Tobias, You will see, not easy task to linearze and to compensate this kind of detector if you need a accuracy.? 1. I sugest you to use some of SPDT switches (well matched, small leakage and small on/off charge transfer)? like ADG819. In this case you will need some power supply from 436 but you need only one 220Hz line. 2. Put some bias trough your voltage doubler diodes, something like 10-20 uA; 3. Replace ground path of the chopper with same diode doubler configuration also biased on the same way like active one. Same capacitors around this one like a "active" doubler. This one doubler configuration (no RF input to this one) will be a new virtual ground and will compensate for temperature drift.? Milan
Hey Jeff,
I didn't see your message, it was not in the other thread!
But thanks anyway, I had the same idea as you suggested - I will soon receive some sensors with a blown thermocouple, and there I probably can replace the thermocouple with my own circuit.
As for now, autozero seems to work, and the sensor provides more or less accurate readings, but it is not terribly accurate. I hope to improve that soon, probably by adding the shaping network HP mentioned.
Best
Tobias HB9FSX
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