| 摘要 |
PURPOSE:To realize a high input inpedance, a low output impedance and a high gain each by constituting a differential circuit with the operational amplifier. CONSTITUTION:Noninverse input terminals B and C of operational amplifiers 1a and 1b are used for the equivalent base and emitter terminals each. And the differential circuit is formed in such way that the output may be extracted out of the emitter follower via the open collector. The sufficient negative feedback is secured inside the operational amplifier along with a high input impedance and a low output impedance ensured originally. Accordingly, a high gain and a low distortion can be attained easily through the differential circuit. And diodes D1 and D2 are provided to equivalent emitter terminal E to ensure an easy logarithmic variation for the gain control characteristics. |
