This circuit was obtained from the March 1994 Electronics Now magazine. The circuit uses a common transistor which can be a low noise type such as the BC549.
In the figure we have the way to implement a 5 to 45 V zener diode with 50 mA of maximum current...
This circuit is a two-channel stereo CMOS mixer with two inputs for each channel. The circuit...
This bench circuit with no active components appeared in the August 1958 Radio Electronics...