Movement detection using light intensity variation measurement - by successive comparison of light density differential derivative w.r.t. time
DE2714663A1
Alarm using electrostatic field detection - has FET as detector responsive to change in local electrostatic field
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Interposing circuit for mobile loads - connects mobile loads to mains supply and ensures correct polarity and earthing by electronic switching
DE2551687A1
Protection system for electrical supply to caravan or boat - checks which is live lead of incoming single phase supply and connects earths automatically
DE2543206A1
Probe for live electrical wires beneath decorations - has transistorized amplifier connected to LED and responsive to electrical field via screw driver blade acting as aerial
CA966079A
Two-bar delivery mechanism on a tow lift
US1081035A
Heating apparatus for drying damp masonry.
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Device for cutting slits in brick walls.
GB190719712A
Improvements in Apparatus for Cutting Slots in Existing Masonry by Drilling and Sawing.
