We found this circuit in a 1964 Electronic Design. Transistors can be modern general-purpose equivalents. The circuit converts a 1 MHz sinusoidal signal into a rectangular signal.
Found in Electronics Now from the 1980s, this amplifier can also be seen in commercial amplifiers...
Found in a Popular Electronics from the 90s, this circuit uses a double 555 to emit beeps when the...
This circuit was found in the January 1992 issue of Radio Electronics magazine. The capacitor...