This Texas Instruments circuit is from the 80's. However, it can be implemented with modern operating systems. The power supply must be symmetrical.
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...