OK on building from parts that you have but be aware that power in Watts = volts x amps so, if you ran 12V at 2A through the circuit you showed with a 1 Ohm resistor and an IRF640:
a. The resistor would dissipate 4W (power in a resistor is amps x amps x resistance (I2R))
b. The FET would dissipate 20W (12-2 (the voltage dropped over the resistor) = 10 x 2A)
This means that they would both get VERY hot so you'd need high wattage resistor and a heat sink on the FET.
Sorry if this is telling you something you already know.
Yes, I'm aware but thanks for warning me.
My sensing resistor is not 1 ohm as in that circuit. It's 2.4 ohm. I didn't have any 1 ohm resistor. So I used 5x 10 ohm resistor (theoretical value should be 2ohm but I get 2.4 ohm).
Anyway, to prevent damaging FEt or resistors, I'm limiting the current to 600mA.
I also can use a light bulb from a desktop chandelier that can consume up to about 1.6A. And I don't need to be careful with heating components.
I did an experiment yesterday with the scope and this light bulb. The chandelier is rated at 12V, 20W max. This light bulb, according to the PSU, at 12V, draws about 1.6A (19.2W).
I don't have enough knowledge to analyse what the results mean.
I tried a few settings with the scope trigger. It was harder and uglier to measure the rising edge OverShoot (and I hope I did it right) than to measure the falling edge OverShoot.
For instance, when measuring the "connecting the load" scenario (rising edge), I can only get measurements from scope at time frames of 100ms and above.
Rising edge @ 100ms - 0.9644% OverShoot
![](https://i.ibb.co/WPfHL3C/DS1-Z-Quick-Print1.png)
Rising edge @ 200ms - 0.3624% OverShoot
![](https://i.ibb.co/WPN5hRq/DS1-Z-Quick-Print2.png)
Rising edge @ 500ms - 0.3496% OverShoot
![](https://i.ibb.co/fHmg2SD/DS1-Z-Quick-Print3.png)
Falling edge @ 2ms - 1.081% OverShoot
![](https://i.ibb.co/r3ytjn7/DS1-Z-Quick-Print9.png)
Falling edge @ 10ms - 0.3539% OverShoot
![](https://i.ibb.co/BgBqxtM/DS1-Z-Quick-Print8.png)
Falling edge @ 50ms - 0.3492% OverShoot
![](https://i.ibb.co/GkZDyCN/DS1-Z-Quick-Print7.png)
Falling edge @ 100ms - 2.306% OverShoot
![](https://i.ibb.co/QfFBnYq/DS1-Z-Quick-Print6.png)
Falling edge @ 200ms - 1.040% OverShoot
![](https://i.ibb.co/qnVkCJX/DS1-Z-Quick-Print5.png)
Falling edge @ 500ms - 0.3487% OverShoot
![](https://i.ibb.co/9224RNv/DS1-Z-Quick-Print4.png)
Power Supply:
![](https://i.ibb.co/1swxWgF/20191124-153623.jpg)
My scope user manual says about OverShoot:
13. Overshoot: the ratio of the difference of the maximum value and top value of
the waveform to the amplitude value.
I can now test with an "heavier" load if needed. About 4A. Is it needed?