| 摘要 |
PURPOSE:To prevent the damage of an adding circuit by providing a third transistor TR where the emitter is connected to the collector of a first TR and the output of a second constant current source and a preliminarily set voltage is given to the base and a load resistance is connected to the collector. CONSTITUTION:A second TR Q2 which has the emitter connected to the emitter of a third TR Q3 as the TR which outputs the addition result, and a preliminarily set voltage is given to the base of the second TR Q2, and the collector of this TR Q2 is connected to a first power terminal. Consequently, an excess current flows to the second TR Q2 though the current more than the current flowing to a second constant current source CC2 flows out from a first TR Q1, and the base current of the first TR Q1 is held in the range of a set value. Thus, the damage of the adding circuit is prevented. |
