This circuit was found in an Electronic World of 1968. The circuit uses power transistors of the time. The transistors are for 25 W of dissipation.
Using a voltage comparator, we find this AND gate on a Popular Electronics from the 90s. The...
This crystal oscillator circuit is indicated for use as a frequency reference in the calibration...
Any operational amplifier can be used in this circuit. The 741 is the most common. Power supply must...