The circuit shown has a voltage gain of 500 times and can use equivalent FETs like the BF245. The circuit is suggested by National Semiconductor in its 1994 Linear Applications Handbook.
With this circuit, a relay can be activated from an alternating signal with frequency up to a few...
With this circuit the visually impaired can easily locate important places inside the house, such...
In the figure we have the way to use the transistors of an old-paired pair as a trigger circuit. The...