This circuit was found in a 1966 General Electric documentation. The circuit makes use of PUTs that are uncommon components today. Counting direction depends on the programming in A and B.
With this circuit it is possible to keep the current in an LED constant even if the supply voltage...
This circuit was suggested by Motorola in its manual of components for optoelectronics (1987)...
This sensitive circuit can be designed with FETs such as BF245 and MPF102. The sensor is a silicon...