This automotive circuit was obtained from an 80's schematic from the integrated circuit factory itself. The voltage regulator is still common, but the operational amplifier is of the time.
This ultrasonic transmitter was found in a 1974 documentation. The receiver is the CIR11753 or...
This circuit was found in the December 1991 issue of Radio Electronics magazine. The circuit is...
The movement of the LEDs in this circuit mimics the back-and-forth movement of a pendulum, making it...