This circuit was found in a 1967 Electronics World. Transistor Q1 can be a TIP321 and Q2 can be a BC558. The indicator lamp is optional.
The circuit shown in the figure consists of a system for driving white LEDs (WLEDs) at low...
In the figures we have an infrared transmitter with a BC337 switching transistor that must be...
The operational amplifiers of this circuit can be replaced with more modern equivalents. The power...