This circuit is from a 1978 Texas Instruments optoelectronics manual. The trimpot adjusts the LED current. Other currents can be adjusted if they are within the capacity of the FET.
This circuit uses amplifiers from the 60's American company Microlin. The circuit can be designed...
This power control from Motorola's 1971 SCR Power Control Fudamentals can control full wave loads...
Despite being from a 1969 publication, the transistors used have current equivalents such as BC548 and...