Externally controlled transistor chopper - has efficiency and reliability increased by using additional transformer and transistor switch

摘要

The eternally controlled transistor chopper has a second transformer (2) and an additional transistor switch (6, 7) whose collector/emitter path is connected in series with a part of the second transformer primary winding (21) to form an auxiliary path, this auxiliary path being in parallel with the main power path. The additional transistor base contacts the clock pulse generator and closes part of the second transformer secondary winding (22), one way over a rectifier (23, 24) and ballast resistor (26) to the base of the power transistor, and the other way to the pole of the direct current supply switch.