Simple Video Amplifier
The video amplifier in the diagram is a well-known design. Simple, yet very useful, were it not for the ease with which the transistors can be damaged if the potentiometers (black level and signal amplitude) are in their extreme position. Fortunately, this can be obviated by the addition of two resistors.
If in the diagram R 3 and R 4 were direct connections, as in the original design, and P 1 were fully clockwise and P 2 fully anticlockwise, such a large base current would flow through T 1 that this transistor would give up the ghost. Moreover, with the wiper of P 2 at earth level, the base current of T 2 would be dangerously high. Resistors R 3 and R 4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA.
Simple Video Amplifier Circuit Diagram:
Shunt capacitor C 4 prevents R 4 having an adverse effect on the amplification.
Simple Video Amplifier
Reviewed by haru
on
June 03, 2012
Rating:
Reviewed by haru
on
June 03, 2012
Rating:
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