555 TV double-channel monitoring automatic conversion circuit

Published:2011/6/15 2:19:00 Author:TaoXi | Keyword: 555, TV, double-channel, monitoring, automatic conversion | From:SeekIC

As the figure 14-14 shows, the conversion circuit is composed of the high duty ratio square-wave generator and the electronic switch, it can be used in the automatic conversion of the two TV channels. The astable multivibrator is composed of the 555 and R1, R2, C1, because the R1>>R2, so the duty ratio is 99%. The IC2 is the six-inverter CD4069. The IC3 which can be used as the inverter phase control electronic switching circuit of the two channels uses the 4-channel analog switch CD4066. It divides the switches into two groups, one group controls the power supply voltage A1 and tuning voltage B1 of the main channel; another group controls the power supply voltage A2 and the tuning voltage B2 of the monitor channel. K is the 2X2 switch that can be used to select the main and auxiliary channels.



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