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.
We found this sensitive moisture detector in an old documentation. The circuit uses a common JFET,...
This circuit for RF signals was found in the March 1987 issue of Radio Electronics magazine. The...
A staircase signal is produced by this circuit using a TTL IC and an operational amplifier. The...