This JFET amplifier stage was found in the Encyclopedia of Electronic Circuits Volume 5 from 1995. Any JFET can be used and the bias controlled externally.
This circuit was obtained from a Hands On-Electronics, an American magazine from January 1987. This...
Using the CA3140 in the figure we have a comparator that goes low in the window voltage space. The...
This circuit is from a Popular Electronics from the 90's. The circuit activates a buzzer with...