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.
SGS's L78xx is equivalent to the regular 78xx. The circuit was found in the SGS manual of linear...
This circuit was obtained in an English publication of 1993. It is an amplifier for...
Found in a Hands-On Electronics from the 90s, this circuit produces the dial tones of an old...