Found in the May 1971 Radio Electronics magazine, this is the circuit for a commercial high-impedance instrument. The circuit uses 4 transistors and is powered by 2 9 V batteries.
Another application circuit for the NE567 is shown in the figure. It consists of a decoder for...
In fact, this is the circuit also known as “vox”, that is, a relay triggered by sound. This...
This circuit can be used with transmitters in the 3 to 30 MHz frequency range also functioning as a...