| 摘要 |
PURPOSE:To prevent an overcurrent from flowing in an output circuit by connecting a resistance to the collector of the input transistor (TR) of a complementary push-pull coupled circuit composed of an NPN and a PNP TR. CONSTITUTION:When an output terminal contacts a power source terminal, the output current I1 flowing through the PNP TR10 is as shown by an equation I1. In this circuit, when an expression holds, the potential at the connection point 15 of the cathode of a bias diode 5 and the base of the PNP TR rises as the output current flows and then a TR7 breaks down. When equations hold, I1¦V0=VCC is about 160mAngstrom . At this time, the expression does not hold. Therefore, there is no breakdown occurring between the emitter and base of the TR7. A current which flows at this time is only the output current shown by the equation I and the current is limited during the short-circuiting of an output circuit through the negative feedback operation of the current amplification factor of the PNP TR10. |
