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.
This circuit, from the ON Semiconductor Thyristor Manual, controls both the speed and direction of...
This high input impedance circuit makes use of two operational ones that are still common. The...
Here we show an oscillator that uses an LC network. The upper limit depends on the power-supply...