Found in an old Popular Electronics, this circuit warns when a remote lighting system is not working. The circuit uses an LDR as a sensor and the components used are quite common today.
This circuit is from 1995 documentation. The power depends on the transformer, which in this case...
This circuit was found in a Popular Electronics of the 1980s. The microammeter may be the lowest...
September 2017 - Littelfuse's Polyswitch SMD Resettable PTCs can now be purchased from Mouser...