Remote Selection Video Switch
Posted on Sep 29, 2012 3632
The A/B Switch circuit consists of three ICs and a handful of resistors. Two gates from a 4011 quad 2-input N
AND gate (U1A and U1B) are configured as a monostable multivibrator that, when switch SI is pressed, triggers a 4017 decade counter/divider, which has been set to recycle after a count of two. The outputs of U2 at pins 2 and 3 are fed to the control inputs of U3 (a 4066 quad bilateral switch) at pins 12 and 13. Depending on which control input is high, either the J1 or J2 output is selected. With a little modification, the switch could be set to trigger at a set rate (automatically). With the addition of another 4066, it could have as many as 8 channels. One possible application would be in a security surveillance system.