rich masel
- Nov 5, 2014
- 14
- Joined
- Nov 5, 2014
- Messages
- 14
Dave: R1 was 5K before I bypassed it so that the input capacitance was 1 uF. Again no effect.
No, it just has a PNP-type input stage. Many op-amps (e.g. LM358, LM324, and many current ones) have input ranges that extend a few hundred mV below the 0V rail. It doesn't have a charge pump, but I'm not saying that it's not oscillating. I couldn't say.This opamp allows inputs below the rail so it probably has a charge pump to create a negative voltage.
Different from what? I suspect Steve would find it easier to help you if he wasn't trying to hit a moving target...Here is a different version of the schematic.
Can you post a picture of your circuit, both sides of the board if it's on a PCB. I'm running out of ideas.