| 摘要 |
PURPOSE:To increase the reliability of transistors (TRs), by inserting 1 or >=2 of Zener diodes between the base and ground of an output TR of a video detection circuit, in the video detection circuit with a black noise reversing circuit. CONSTITUTION:Since a Zener diode 22 is inserted between the base and ground of a video detection output TR12, even if the input signal at an input terminal 1 is in any state, the base voltage of the TR12 does not exceed the dielectric strength and no reverse current flows to the base-emitter of a TR14. Thus, the TR14 is operated at a region without problem on reliability at all times. |
