What Must todo

Overview
The construction of the circuit has been increased to highlight and amplify video signals for further frequencies on image clarity.

Video Signal Amplifier Circuit diagram


Terminology

LH0024 – IC small signal IC designed for general purpose switching and amplification due to its low voltage, low voltage and three different win the election 1N4148 – silicon small signal diode planar epitaxial used for fast switching applications with a reverse voltage of 100 V and forward current of 150 mA

Circuit Explanation

In a video output signal is the high rate of frames selected for amplification of producing a finer. This is possible by placing the track between the video device and the reception lobby, where the video port of the television receiver is inserted. The construction is done simply by exploiting the operation of three transistors instead of IC and other supporting elements.

An isolator operating in the first phase of the Q1, which provides an interface for input impedance. Q2 manage the second phase, which leads to the common base configuration. In this phase, determine the earnings TR2 250 ohms cutting the lawn. To adjust TR2, it must be placed where an output voltage of 1 Vp-p is present, with a load of 75 ohms. The frequency response is regulated by a combination of R6, C3, and 500 ohms TR1. An output buffer is completed by Q3 of the third phase which provides an airline pilot with 75 ohms. The range of the circuit is stabilized with 12 V and 50 mA.

Video amplifier circuit is simple and can be used. Video amplifier circuit was constructed from 2 pieces of transistors BC550 and BC560. The source voltage used for supplying the video amplifier circuit is 5VDC. Video amplifier circuit is equipped with a powerful regulator which flows through both transistors T1 and T2, the components used to manage these flows are P1 and P2.

Then the video amplifier circuit is also equipped with limiting the maximum current that passes through T1 and T2. The components in black block functions as limiting the maximum current that is passed by the T1 and T2 for no more than 5mA.

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 R3 and R4 were direct connections, as in the original design, and P1 were fully clockwise and P2 fully anticlockwise, such a large base current would flow through T1 that this transistor would give up the ghost.

Moreover, with the wiper of P2 at earth level, the base current of T2 would be dangerously high. Resistors R3 and R4 are sufficient protection against such mishaps, since they limit the base currents to a level of not more than 5 mA. Shunt capacitor C4 prevents R4 having an adverse effect on the amplification.

Author: L.A.M. Prins

Copyright: Elektor Electronics

Source: http://www.extremecircuits.net/2010/07/video-amplifier.html