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.

Constant Current Source for LEDs (CB915E)
This circuit uses a FET to drive an LED with constante currente. The current up to 20 mA can be...
Two Stereo Light Effects (CB17150E)
This circuit was found in a 1999 publication. Its purpose is to flash two LEDs according to the...
FET Voltmeter (CB18924E)
With this voltmeter with high input resistance, voltages from 10 mV to 50 V. can be measured. FETs...