Powerful IR Emitter (CB26030E)

This modulated circuit was found in the November 1997 Electronics Now magazine. The power transistor can be any MOSFET,

| Clique na imagem para ampliar |

High impedance window comparator (CB6091E)
General Electric suggests this circuit in a 1980s documentation. The operational of the time is...
Passage Alarm (CB12894E)
This circuit, from a 1973 publication, locks the relay when the light that falls on the LDR is cut...
FM Tuning Indicator (CB16434E)
This circuit can be adapted to an FM radio or other receiver that does not have a tuning indicator LED....