Transistorisierte elektrische Schaltungsanordnung zum Schliessen und Öffnen eines Stromkreises

1,121,477. Transistor switching circuits; pulse modulating circuits. ATOMENERGI A.B. 2 Dec., 1965 [3 Dec., 1964], No. 51273/65. Headings H3T and H4L. In a circuit for switching or chopping a signal appearing between two terminals a and b, of the type in which a first transistor T 1 has its emitter and collector connected to a and b respectively and a second similar transistor has its base and collector connected respectively to a and b and in which the base of T 1 and emitter of T 2 are supplied with equal and opposite control signals in one state of the switch, the control signals are provided by an amplifier or a transformer. It is explained that in the basic circuit the current in T 2 reduces the offset " voltage across T 1 and the currents in the depletion layer capacitances balance out during switching. The amplifier shown, which is of polarity reversing type, may have its input connected to control terminal C and either the emitter of T 2 (as shown) or the base of T 1 . Alternatively, the input and output of the amplifier may respectively comprise (as in Fig. 3, not shown), a bias supply resistor (R 1 , R 2 ) and a transistor (T 4 , T 5 ) shunting the input and output circuits. These transistors are fed with the control signal at their bases and provide a short-circuit to line a-b when the switch is off. A phase-splitting transformer may replace the amplifier (Fig. 4, not shown).