| 摘要 |
<p>1,167,397. Transistor switching circuit; automatic exchange system. TELEPHONE MFG. CO. Ltd. 11 July, 1968 [21 July, 1967], No. 33635/67. Headings H3T and H4K. A two-pole electrical static switching device comprising a complementary pair of bipolar transistors having their respective emittercollector paths connected in the respective pole circuits through the device, and their bases respectively connected to the source and drain electrodes of a unipolar F.E.T. the grid of which serves to receive a control signal to operate the device between the ON and OFF conditions. In Fig. 3, complementary transistors TR1 and TR2, TR3 and TR4, form the switches which connect devices TL1, TL2, respectively, to the common supply lines of C1 and hence to each other. A negative pulse, or 1, appearing at both CP1 and CP2, will turn on respective FETS 1, 2, and hence connect devices TL1 and TL2 via Cl. These pulses are obtained from AND gates A1, A2, fed by a synchronizing 1 pulse and a pulse from a shift register which determines whether the FET is turned on. It is possible to hold a FET turned on by means of high-frequency pulses because of the charge retained by the gate-substrate capacitance. Fig. 2 shows a possible switching matrix using cross-over points of Fig. 3.</p> |
