This circuit is from a 90's documentation. The circuit is simple, as it uses only two transistors, and the control is done by pressure switches. The indication is done by LEDs.
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...