| 摘要 |
693,061. Semi-conductor devices. WESTERN ELECTRIC CO., Inc. Feb. 9, 1951 [Feb. 18, 1950], No. 3201/51. Drawings to Specification. Class 37. [Also in Group XL (c)] An electric signal translating device comprises a semi-conductor body having a low resistance connection and a rectifying connection which is used to inject charge carriers of the sign opposite to those normally present in the semi-conductor, and means including reverse direction pulses to periodically remove the injected charges which are utilized in a load circuit. If the collector electrode of a transistor comprising emitter, collector and base electrodes is supplied with a square voltage pulse of one microsecond duration in the reverse sense (i.e. negative pulses if the semiconductor is of N-type material), the collector current is shown to be dependent on the immediately prior conditions existing in the emitter circuit. If no emitter current has been flowing, the collector current reaches a small value for the duration of the pulse, but if an emitter current of say one m.a. has been flowing providing a supply of current carriers in the semi-conductor, the collector current rises to a high value at the commencement of the pulse and then decays during the pulse towards the steady state level determined by the emitter and collector voltages concerned. Similar characteristics may be obtained by using only one electrode which is used alternative as emitter and collector. The application of the device to a pulse code modulation system, and to a pulse position modulation system is described. |
