This circuit is from the 80's but uses common components today. The relay is voltage sensitive according to the power supply used. Transistors may be general purpose types.
In a voltage follower, the gain is unitary, and the input impedance is very high. The output...
This circuit, from an old 1988 publication, generates bars on the screen of an old analog TV for...
This circuit is from a Motorola integrated circuit manual. The integrated used is no longer common...