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| Current measurement from 0.1uA to 1A |
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| Kleinstein:
The logarithmic curve would not be that bad. A problem is that the diode voltage is also temperature dependent. With nonlinear self heating this can get quite tricky is good accuracy is required. The two or 3 range version is probably the better way. |
| Kalvin:
--- Quote from: Kleinstein on December 05, 2018, 09:14:50 pm ---The logarithmic curve would not be that bad. A problem is that the diode voltage is also temperature dependent. With nonlinear self heating this can get quite tricky is good accuracy is required. The two or 3 range version is probably the better way. --- End quote --- EDN has a Design Idea for logarithmic current measurement circuit using carefully selected diodes: https://www.edn.com/design/test-and-measurement/4443319/Multi-decade-current-monitor-the-epitome-of-simplicity I have no idea how well this will work in real life with real components and/or how hard it would be to find a suitable diode pair. But very interesting idea anyway. |
| sandy.holmarc:
How quickly do you need to be able to measure the current? Can you tell us something about the application as it would help us understand your requirements better? [/quote] Hi splin, Thank you very much for the reply.I would like to develop a VI measurement circuit for the solar cell experiment.Measurement time under 3 minute is fine .I need accuracy of 10nA only in uA range measurement ,uA accuracy in the mA range measurement and mA range accuracy in the A range measurement . |
| Marco:
Given how often this topic come up, I think Dave should do an auto-ranging multi-output uCurrent. Have 3 shunts in parallel, with the lower value shunts gated by a bidirectional switch (back to back MOSFETs). When the absolute voltage across the previous shunt goes over a threshold, start smoothly switching in the next shunt. |
| Habropoda:
It seems like the CurrentRanger could handle this: https://lowpowerlab.com/guide/currentranger/ |
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