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.

[rolfdegen]

Hello..

The Siglent SPD3303X-E laboratory power supply arrived today. What can I say ... I'm verry happy.
The Siglent power supply is super quiet. In addition to Rigol DP321 power supply, you can now work relaxed
and even listen to music 

I just don't understand why the Rigol DP831 power supply is so loud after being switched on 
After switching on, the fan starts up and then constantly at medium speed.
Perhaps the power transistors in the power supply are "preheated" like in the diesel before the start 

Conclusion: Although the Rigol DP831 power supply compared to the Siglent laboratory power supply more adjustment
and Possesses analysis functions (even a system temperature display), I will ultimately
opt for the Siglent laboratory power supply and send the other one back.

Greetings Rolf