earckens
Member
A pcb made according to the schematic (attached below) uses LM324 opamps. With no input signal to the current transformer pin 3 should be low, and pin 2 follows feedback from output pin 1 (high).
Two of the opamps give 0.0V on their pin 1, but two opamps measure approx. 2.5V on their outputs.
All components are correctly soldered with correct values on the pcb, hence I would expect five identical results.
Pcb traces to pins 2 and 3 are just millimeters long, and as short as possible.
Jumpers SJx are not soldered.
I swapped IC's around, but still the same circuits of the five do show this behaviour, hence unrelated to the IC's.
Why are two outputs not near 0V?
Two of the opamps give 0.0V on their pin 1, but two opamps measure approx. 2.5V on their outputs.
All components are correctly soldered with correct values on the pcb, hence I would expect five identical results.
Pcb traces to pins 2 and 3 are just millimeters long, and as short as possible.
Jumpers SJx are not soldered.
I swapped IC's around, but still the same circuits of the five do show this behaviour, hence unrelated to the IC's.
Why are two outputs not near 0V?
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