Circuit arrangement for voltage limitation during disconnection of the dc circuits with inductive differential vita

摘要

The voltage limiter, for d.c. inductive-load transistor switches, has a voltage divider with its first resistor (R1) across the transistor switch collector/base junction and its second resistor (R2) across the transistor emitter/base junction. The inductive load--e.g. relay--is connected into the transistor collector circuit, and the switching signal is applied over a resistor to the transistor base. The two resistors in the voltage divider are dimensioned so that the voltage across the second resistor (R2) when the transistor is off is less than the cut-in voltage when V(CE) is equal to the supply, and greater than the cut-in voltage at V(CE-Max).