EEVblog #828 - Siglent SPD3303X precision Lab PSU Teardown

[alm]

Imagine you want to test a low-power LED. You set the current limit to 1 mA, and leave the voltage limit set to 30 V, since limiting the current should be sufficient. Now you connect your LED to the power supply. The output cap will be charged to 30 V, and is not subject to the current limit (it is located beyond the pass transistor). This capacitor will dump all its energy into the poor LED. The current will only be limited by the ESR of the cap, resistance in wiring etc. The bigger the cap, the more energy will be dumped in the device under test in this scenario.

[hkBattousai]

I understood it. Thank you very much.