We found this circuit with the LM3914 IC in a Radio Electronics magazine from June 1985. The circuit is intended for monitoring the battery voltage through an LED bar.
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...