GB1403222A - Device for rapid switching of inductors - Google Patents

Abstract

1403222 Transistor switching circuits CARL ZEISS JENA VEB 24 July 1972 34493/72 Heading H3T In a device for rapid switching of inductors, an inductor 1 is connected by means of a main switching transistor 2 to a source of voltage Ub 1 , an auxiliary transistor 5 being connected in series with the inductor 1, auxiliary transistor 5 connecting the inductor 1 during the switching- on period to an auxiliary source of voltage Ub 2 higher than that of the first source for causing the current in the inductor to rise steeply during the switching-on period, the auxiliary transistor 5 being controlled by a circuit comprising a control transistor 28 and a R-C network 25, 26 the operating time of which is so adjusted that the auxiliary source of voltage Ub 2 is disconnected when a desired value of current has been reached. A positive pulse applied via diode 4 and resistor 4 to the base of transistor 27 renders the latter conductive, whereby transistor 29 is biased non-conductive and so biases transistor 2 conductive. The pulse at the collector of transistor 27 is differentiated by differentiating circuit 25, 26 so that the leading edge of the pulse biases transistor 28 non-conductive for a short period: during this period transistor 5 is biased conductive so that inductor 1 is energized from source Ub 2 , but at the end of it energization is from the lower voltage Ub 1 alone.