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.

Automatic High and Low Light (CB16257E)
We have here a very interesting project found in a 1982 publication. By the operation of the...
Two Transistors RC stage (CB4681E)
We found this circuit in an old American manual. The formulas allow the gain to be calculated as a...
Dwell Meter (CB4961E)
This circuit is from the time when cars used contact breakers. This 80's version measures the dwell...