This proximity sensor was found in a 90s Popular Electronics. The base is a PLL567 that operates at around 100 kHz. The circuit operates by capacitance sensing.
This LED signaling circuit uses a programmable unijunction transistor (PUT) as a relaxation...
This decoder filter was found in a 1975 documentation. The integrated circuits can be 741. The...
We found this circuit in the January 1997 Electronics Now magazine. The triac determines the...