This circuit was found in a 1964 Electronic Design. The components are of the time, and modern equivalents can be used. Note the multi-emitter transistor.
This circuit was found in a 1974 publication. It provides a tone indication of the temperature sensed by...
This is a simple rheostat circuit for motor control that works with voltages from 6 to 12 V. The...
This circuit with TTL compatible output was found in a 1968 US documentation. The circuit is...