Based on the CA3140 IC, this circuit was found in the June 1986 issue of Radio Electronics. Sensitivity adjustment is made using a trimpot in series with the sensor.
SST OXY Flex Oxygen Sensor The purpose of this SST sensor is to measure oxygen level in enclosed...
The basic idea of this 1988 circuit is to use a signal called REMOTE existing in some types of...
With each touch on S1, an output of 4017 is activated, this in sequence 3, 2, 4, etc. These...