100 Hz Second Order High Pass Filter (CB25815E)

This filter with the 741 op amp was found in the February 1995 Electronics Now magazine. The power supply must be dual.

AND gate LM139 (CB21028E)
Using a voltage comparator, we find this AND gate on a Popular Electronics from the 90s. The...
100 kHz Crystal Calibrator (CB3926E)
This crystal oscillator circuit is indicated for use as a frequency reference in the calibration...
Operational Amplifier Touch Switch (CB3853E)
Any operational amplifier can be used in this circuit. The 741 is the most common. Power supply must...