GB1108671A - Improvements in diode gate circuits - Google Patents

Abstract

1,108,671. Selective signalling. INTERNATIONAL BUSINESS MACHINES CORPORATION. 13 April, 1965 [13 April, 1964 (2)], No. 15606/65. Heading G4H. [Also in Division H3] In a switching circuit having a diode D connected in series with an alternating voltage signal source G and a load ch, the diode is either forward or reverse biased by a biasing means, e.g. transistor T so that when the peak voltage of the alternating voltage signal is greater than an applied forward bias voltage and because the period of oscillation of the signal source G is less than the charge storage time of the diode the diode conducts linearly for each cycle of the signal to transmit the signal to the load substantially without distortion, whereas when the reverse bias is applied the signal is not transmitted. Two circuits may be arranged in series with the diodes back-toback so that both diodes have to be biased on for an output to occur in the load (Rij, Fig. 4, not shown). The second diode is biased by a transistor of complementary type to that used for controlling the first diode. This form of circuit may be used in an array of switching circuits (Fig. 3, not shown), in which m switching circuits, e.g. Dlo-Dio-Dmo, are connected in parallel to the signal source G and in which n switching circuits, e.g. Dll, Dlj, Dln, are connected in parallel to each of the m switching circuits. The loads, e.g. Rmn, Rij, Rll, are each connected to the signal source via two back toback connected diodes (Dmn, Dmo) when they are both biased on.