| 摘要 |
<p>Transistor switching means in which a principal transistor (T5) feeds into a load (Rc) when a control signal saturates a control transistor (T1), a resistance bridge (R3,R4) fed by a source (VAL) then polarizing the base of the principal transistor (T5). An auxiliary transistor (T3a) has its base coupled to the collector of the transistor (T5) by means of a diode (D2a) and one of the two polarization resistances (R10-R11). When the collector-emitter voltage of the principal transistor becomes too strong as a result of a short-circuit in the load, the auxiliary transistor (T3a) is saturated and blocks the principal transistor (T5). Application to detectors of the type having an electro-luminescent diode excited by pulses; these pulses, applied to the auxiliary transistor (T3a) block it momentarily in order to ensure the re-setting of the circuit when the overload has disappeared.</p> |
