This circuit that can be activated by light or heat was found in an old American documentation, but the components it uses are perfectly current. The power transistor shall be fitted with a heat sink.
This circuit operates with an AM radio tuned to or near 900 kHz if there is a station at this...
This circuit was found in a 1965 General Electric documentation. SCRs and unijunction may be...
Found in a 90s Popular Electronics, this circuit uses a simple 9 V source. The power can be used...