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.

Dual Frequency Generator (CB16305E)
What is a dual frequency generator for? There are several possibilities of use for this circuit. The...
4-input stepper motor control (CB23786E)
The circuit, illustrated in the figure, consists of the direct application of the ULN2003 in which...
Ultrasonic ear (CB21314E)
This circuit was found in a Popular Electronics from the 90's. The output signal can be applied to a...