Video Wire Circuit Schematic Diagram : Enables Video Transmission Through Long Cables


With this circuit, you will be able to connect your camera with a very long wire. It actually is a video amplifiers. The amplifiers is used to make a stronger signal at the sender part, which then transmitted via long cables. It is transmitted using balanced mode where two wires are driven in the opposite phase. Following is the schematic :

Video wire (receiver) circuit schematic

Video wire (sender) circuit schematic

IC MAX433 transconductace amplifier is the core of this circuit. It has wide bandwith features which suitables for video signal application. The balanced mode in this video wire circuit makes sure that any noise exposing the cables at the receiver would cancel each other.

The typical four conductor flat 28 gauge telephone wire have the resistance 7 ohms per 100 feet. The total series resistance is about 14 ohms per 100 feet, due to voltage drops in the plus and minus power supply leads. Maximum allowable wire length depends on the total current requirements of the camera and send board. Using a camera that draws 100 ma, for example, a total current of about  180 ma is required and therefore a maximum of approximately 500 feet of  28 gauge flat telephone wire can be used. If a longer wire is needed, the round type of  22 gauge four conductor telephone wire offers much lower resistance. Its resistance per 100 feet is approximately 3.3 ohms total for both the positive and negative power wires. Using this wire and a 100 ma camera, the wire length can be approximately 2000 feet.

[Schematic diagram source: aeiproducts.com]


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