This circuit is from an American 80's documentation. The integrated circuit is from the time and the sensor consists of a smoke chamber measuring its transparency change.
This circuit has both frequency and duty cycle control. We found it in the October 1992 Radio...
This circuit uses the 7493 to divide a TTL square signal by 8. The circuit must be powered from a...
This circuit is basically the same configuration as the previous one with a power stage with...