Hello,

I try to test different Powersupplies with
USB DC 0-3A 3-20V Adjustable Constant Electronic Load

It works, if the powersupply delivers enough current for startup. The testmodul needs a strong ampere-peek when plugging it into the powersupply. Some of my powersupplies break down, when I plug in the tester. Even with currentregulators on min. When I use my Labor-Powersupply and set it to 5 volts and to a current limit of 500mA and plug in the tester the voltages goes down to about 2,5 Volt with a current of full 500mA limited by the supply. The tester is nearly a short to the supply and pulls 500 mA. And therefore it ist not useable for a lot of supplies. Some stronger supplies can give the pulse and all works correct after plugging in.