Installing the camera in office, home, or the shop becomes economically feasible because the price of security camera going down. It is not efficient if we provide a dedicated monitor for every installed camera. If the CRT monitor is used to display static image from only one camera, it might suffer phosphor burn. So we need video switcher circuit to display 1, 2, 3, or 4 cameras in one monitor. Here is the circuit :
This circuit uses MAX454 video multiplexer-amplifier from MAXIM as the core of this circuit. When designing the video signal path around this chip we must take care about it. To prevent noise interference and crosstalk, track or ground plane can be inserted between video signal channels. We must solder the chip directly to the PCB. It is a bad idea if we use socket for ic. The CD4017 sequencer driving the channel indicators (LED1-LED4). D1…D4 decode the output of this sequencer to 2 bit binary data to address the MAX454 multiplexer.
