This circuit was obtained from the Encyclopedia of Electronic Circuits volume 5 of 1995. The circuit uses the 4001 CMOS to obtain hysteresis in the sensor feedback.
This circuit was found in old documentation. PUTs are uncommon components today. The circuit...
This circuit was obtained in a 1991 Electronics Handbook. The publication no longer exists, but...
This crystal oscillator generates a 20 MHz signal. Equivalent transistors such as BF494 and 2N2222...