Published in a PE Hobbyst Handbook of 1991, this sensor uses an integrated circuit that is unusual today. The circuit is based on a high frequency oscillator.
Found in a 90s Electronic Design, this circuit produces a pure 3 750 Hz sinusoidal signal. The...
We found this circuit in an old publication (1977) using common transistors at the time and now...
This circuit is based on operational ones found in documentation from the 90s. The frequency with...