This circuit was found in documentation for radio amateurs of the 1980s. This is the so-called roger-beep, which is the beep that is transmitted when the talk-listen function is changed.
This configuration is from a 1964 US documentation valid for any FET. The range of power voltages...
Only the right combination of the positions of the 6 rotary switches of 1 pole x 10 positions of...
Another of the many anti-bounce circuits that we have in this section of our website. This one...