This circuit is from Motorola's 1990 Linear Databook. The transistors allow equivalents and the output power depends on the supply voltage. The power supply must be 30 V symmetrical.
The current accross the LED as function of the resistor value is given by the formulas. The...
June 2017 - NXP's new 4 Mbit capacity NXH5194 memories are available from Mouser Electronics...
This circuit was found in a 1989 documentation. The circuit directly controls a power load by the use...