Found in American documentation from the 1980s, this circuit can be designed with equivalent components. The microphone can be of the piezoelectric type.
In the figure we have an application for NLAS5113, a new device from on Semiconductor...
This circuit was found in an old American documentation on telecommunications. It is suitable for...
This circuit can handle 25 A unde a 32 V voltage using a hight power old transistor. This...