Electronics > Beginners
Oscillations with LM358 electronic load
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salami738:
Thanks to all contributors, you have helped me a lot.
I will post an updated schematic, when it works!
Kleinstein:
The IRF530 should also work. However it's still a relatively low voltage FET with high trans-conductance and may thus show thermal instability at higher voltage. So it's likely OK up to maybe 20 V or so. At higher voltage one may have to reduce the power limit to be on the safe side.

Estimating the real SOA is difficult. There are some MOSFETs extra specified / designed for linear operation, but these tend to be expensive.
salami738:
Current schematic:


Features:
- cheap, many components from aliexpress (main mosfet costs around 1$ at lcsc)
- can be scaled by adding more "load units" (dashed line)

Problems:
- slight current drift over time (about -1% below 500mA and around +/-0,5% above)
- initial set point (V1) is not stable. For 1A of constant current, one needs around 1,101V to 1,114 - +/- 1,2%)

I think I will counter the open problems with software.
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