The RCA integrated circuit used in this control is uncommon today. The circuit is from an Electronics Now from July 1995. The sensor determines the value of the adjustment potentiometer.
This circuit uses a 100 kHz crystal, but nearby frequencies can be obtained with appropriate...
Found in an Electronic Design from the 90's, this circuit supplies voltages of 5 V and 3.6 V from...
September 2017 - Texas Instruments PCM186x and PCM186x-Q1 Audio ADCs can be found at Mouser...