| 摘要 |
PURPOSE:To obtain a large output with excellent frequency characteristics by driving a final-stage active element series-connected by an emitter follwer or source follower and by making respective active elements equal in driving impedance. CONSTITUTION:In case of extracting a large output by series-connecting transistor TRs 4 and 8, and 5 and 9, Trs 8 and 9 becomes greater in driving impedance than TRs 4 and 5 since values of resistances 10 to 13 are greater than that of signal- source resistance 2, so that frequency characteristics will be bad. For the purpose, TRs 14 and 15 are used for driving TRs 8 and 9 by an emitter follower. As a result, the values of resistances 10 to 13 van be made small without decreasing the input impedance, i.e. the voltage gain. Therefore, the unbalance of frequency characteristics can be eliminated by adequately selecting those resistance values. |
