| Electronics > Projects, Designs, and Technical Stuff |
| Weird signal instablity of an opamp amplifier |
| << < (5/5) |
| StillTrying:
In a room with mains, a PSU, a SG and a scope all connected, 0.5mV of total noise on a 10mV signal might be about the best you can get. Have a good thick GND. Decoupling caps very near the op amps supply pin(s). Make sure there's no noise on the inverting amps +ve input. Some of the fast SMPS spike noise won't be real - just picked up by the scope's probes and GNDs, at these frequencies you could use the probe on X1 to filter some of it. Lower all the impedances quite a bit. After that it's a full GND plain and screened box. That's all I can think of! |
| HB9EVI:
Depending on your setup, it's very likely common mode noise. If you use the scope probe with long ground tail clip, then you very likely have culprit. The only way to be sure, that the circuit is clean, is keeping the ground connection between circuit and scope as short as possible |
| Navigation |
| Message Index |
| Previous page |