| Electronics > Projects, Designs, and Technical Stuff |
| DVMs aren't benign |
| << < (3/3) |
| Doctorandus_P:
I think that Dave did a trouble shooting video recently of his own uCurrent. If I remember well, a (substitute) opamp had stability issues when loaded with cables and meter impedances and started oscillating. So, even when meauring DC, check for weird stuff with your scope. |
| Dave:
--- Quote from: Doctorandus_P on February 03, 2019, 09:16:09 pm ---I think that Dave did a trouble shooting video recently of his own uCurrent. If I remember well, a (substitute) opamp had stability issues when loaded with cables and meter impedances and started oscillating. So, even when meauring DC, check for weird stuff with your scope. --- End quote --- In that particular case, it was not really a problem of opamp choice, but bad circuit design. |
| Conrad Hoffman:
Finally got back to this and concluded that the 3478 doesn't contribute much. The shift is caused by the 3455, but I think it's just hum pickup, as properly connecting the shield reduces the error to near zero. |
| Navigation |
| Message Index |
| Previous page |