This sophisticated circuit with two LF411 operational amplifiers appeared in the November 1984 issue of Radio Electronics magazine. The circuit uses a Mallory buzzer as an indicator.
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...