| 摘要 |
1321946 Transistor amplifying circuits SONY CORP 19 April 1971 [26 March 1970] 25015/71 Heading H3T In an arrangement for preventing overload of a transistor Q2, e.g. if the load L is shortcircuited, an auxiliary transistor Q3 has its collector-emitter path in shunt to the signal input to transistor Q2, and its base is connected to a network of resistors R1, R2, R4, R5 which combines a voltage proportional to the current in transistor Q2, developed across resistor R1, with a voltage proportional to that applied to the collector of transistor Q2. The proportionality is modified, to avoid the arrangement coming into action in normal operation, by means of diode D1 and resistor R3. A further diode D2 prevents transistor Q3 becoming conductive on negative signals. The arrangement is shown duplicated, as applied to a single-ended push-pull amplifier comprising transistors Q2, Q2<SP>1</SP> driven by transistors Q1, Q1<SP>1</SP> respectively. To prevent the arrangement coming into operation when the load is inductive, the diodes D1, D1<SP>1</SP> may be biased in accordance with the signal output by means of separate rectifier circuits comprising diodes (D3, D3<SP>1</SP>) connected to the output load (Fig. 6, not shown) Reference has been directed by the Comptroller to Specification 968,839. |
