Found in a documentation from the 90's, this circuit uses only one integrated circuit. The resistors in series with the LEDs depend on the power that can be between 5 and 12 V.
This circuit consists in a capacitor bridge for capacitance measurements. The circuit can be...
This switched circuit was found in an old documentation and no information about the transformer...
This circuit was found in an American 1980s documentation. The transistorized step is the...