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.
Found in RCA documentation from the 1970s, this circuit is intended for firing thyristors in inverter...
This micro FM transmitter or wireless FM microphone makes use of a ceramic capsule as a microphone or...
This circuit is from the November 1974 issue of Radio Electronics magazine. The capacitor...