Based on a 555, this 80's American documentation circuit detects the voltage of a battery and can then disconnect the charger. The transistor may be a general purpose type.
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...