| 摘要 |
1510320 Transistor amplifier SONY CORP 2 May 1975 [10 May 1974] 18511/75 Heading H3T A sensing circuit comprises a bipolar transistor 10 with an extra gate region 4G, of the same conductivity type as the base, embedded in the emitter region within the minority carrier diffusion distance from the emitter-base junction (Fig. 3, not shown). The conductivity types of the regions may be reversed. A varying resistance sensing element 15 is connected between gate and emitter, forming with the internal base-gate resistance a potential divider controlling by alteration of resistance 15 the gate potential over the range from base to emitter potentials. This in turn swings the operating mode from high gain-high collector current when the gate is at base potential to low gain-low collector current when at emitter potential (Fig. 7, not shown). By variation of the setting of base current by bias control 20, the condition for maximum sensitivity of collector current to resistance 15 change may be selected. The sensing device may respond, e.g. to temperature, magnetic field or light. A trigger circuit to switch at a selected level of the sensed parameter, or with interposed differentiating circuit to switch within a selected range, may be connected to output terminal 22. |
