Here's something new.
I replaced the zero pot with a new one due to the bad connection. I let the unit run to check the operation and I got the graph shown here.
I determined that the pattern was due to my house heat cycling on and off. The detector's chassis was closed but it was still affected by the changing temperature of the room air. I'm going to have to insulate the circuitry. It must be the resistors being affected by the temperature. I never thought they'd be so sensitive.
I determined that the pattern was due to my house heat cycling on and off. The detector's chassis was closed but it was still affected by the changing temperature of the room air. I'm going to have to insulate the circuitry. It must be the resistors being affected by the temperature. I never thought they'd be so sensitive.
Rd values are 820 ohms, Rs is 1.46K ohms, same as the last run. The diff amp output was 3.739V, to begin with probably due to diffrent overall resistance of the new zero pot compared with the old. I readjusted the zero pot to bring the output closer to zero so the software would show the signal amplified for clarity.
(Actually the zero pot wasn't exactly centered.)Attachments
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