GB992644A - Circuit control by transistor switching circuits - Google Patents

Abstract

992,644. Transistor switching circuits. CHARBONNAGES DE FRANCE. March 20, 1962 [March 1, 1961], No. 10662/62. Heading H3T. In a switching circuit comprising a transistor switch 3 connected in series with a load 1 across an accumulator 2 which supplies current to energize the load when the transistor is switched on, switching means is provided, in one position of which the transistor is rendered conductive and another position of which charging current is supplied to the accumulator, diodes 10 and 11 being so connected into the circuit that no current is supplied to the accumulator when the transistor is rendered conductive and no current is supplied to the transistor when the accumulator is being recharged. Thus with the switchcontact arms in their upper position, current supplied via diode 11 establishes a potential difference across resistor 5 such as to render transistor 3 conductive, diode 10 being at the same time cut off. With the contact arms in their lower position current passes via diode 10 to charge the accumulator and diode 11 is cut off. With the contact arms in an intermediate position transistor 3 remains cut off. the leakage current through the transistor being reduced by the high impedance shown by silicon diode 4 for small currents. The battery 8 and switch 7 may be connected to the transistor circuit via twowire line 6 to provide remote control of the load device 1.