This circuit uses a Motorola component from the 90's and is suitable for the diode-transistor logic of the time. The circuit can be adapted to use more modern equivalent logic.
In the figure we have the way to implement a voltage doubler in a simple source. The component values...
This circuit, which has a power of a few tens of microwatts, is suggested by Maxim. The circuit has a...
With the name of detectaphone, we find this circuit in a documentation from 1966. It will be...