Found in a 1967 documentation this circuit can be applied to any operational amplifier. Components without values determine the frequency to which the circuit is tuned.
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...