An indispensable tool for testing power supplies, assemblies, and power amplifiers. Numerous electronic fuses, such as overvoltage protection and reverse polarity protection, ensure optimal safety during testing. The LED indicators for overcurrent, overload, overtemperature, reverse polarity, and load disconnection allow for immediate identification of the cause of the automatic shutdown of the electronic load. The setpoint adjustments for resistance and current sink operation can be made continuously.