Summary This article shows that transistor choppers can compete technically as well as economically with SCR-choppers. The principle of a buck converter is briefly explained, and measures for the protection of electronic switches (single, or parallel array of transistors) against overload are stated. An overload on an electronic switch in ON-state is prevented by detecting the voltage which is on its main current electrodes and by turning this switch to its OFF-state for a certain period of time as soon as a certain limit has been reached. So-called relieving circuits (di/dt-and du/dt-limitations) without loss due to construction principles, which relieve the electronic switch during turn-ON and turn-OFF from undue power dissipation and which prevent the occurrence of excessive reverse voltage immediately following turn-OFF will be discussed and explained using oscillograms. These measures result in a simple, fail-safe and cheap chopper which, compared to a SCR-chopper, can be operated at a higher pulse repetition rate, whose switching states “continuously ON” and “continuously OFF” can easily be managed, and which, finally, - due to the lack of a forced commutation circuit - can be turned OFF at any time and under any load condition.