Optical sensor for PC (CB20548E)

This circuit was found in a PC documentation from 1996. It can be used as a shield with modern microcontrollers.

Diode Bridge Power Supply (CB4244E)
This is the traditional configuration of an unregulated bridge rectified power source. The circuit...
Metronome 1 - 4093 (CB6889E)
In the figure we have a circuit that produces interval pulses, reproduced in the piezoelectric...
1 kHz high pass active filter (CB7576E)
Found in American documentation from the 90s, this circuit passes frequencies above 1 kHz. The...