This circuit can work with almost any JFET. The circuit is from an Electronics Now from April 1993. It is powered by a 12 V battery, but can also be powered by 9 V.
Found in an English documentation from 1989, this circuit uses components common today. The...
The LED frequency flashes depends on the value of the capacitor tested according to the table. We...
Found in a Popular Electronics from the 90s, this circuit generates a signal that depends on the...