We found this circuit in an old American documentation, but the circuit can still be assembled with ease as the used components are still available. MOSFETs admit equivalents.
We found this circuit in a 1998 documentation. It senses the passage of people or objects through an...
This circuit is from a Linear datasheet. The circuit provides a 5 m voltage with 40 mA from an AA...
We found this circuit in a 1995 paper. The reed switches are surrounded by a few coils of coarse...