This circuit uses a photo-SCR or LASCR that is not a common component today. The relay depends on the load, and the power is supplied by the power grid.
This circuit suggested by Intersil, provides a Kelvin scale of 3 and a half digits in a 7106, with...
This circuit suggested by Motorola can be used as LED high frequency modulator. One possible...
This LED diode test is suggested by the Texas Instruments optoelectronics manual. The transformer current...