Two-component photorelay (CB22087E)

This circuit makes use of an ultrasensitive relay or reed-relay. LDR supports equivalent.

Telephone Call Activation (CB17449E)
This circuit, from a 1999 publication, uses an improvised optical coupler with LED or...
Voltage doubler (CB9442E)
Found in Radio Electronics from the 90s, in the figure we have conventional voltage doubler with...
TPS92515 2 A LED driver (COM096E)
September 2016 - Mouser Electronics already has in stock the new IC TPS92515 LED driver from Texas...