capacity relay

The capacity relay consists basically of an oscillator, a detector and a relay driver stage. A length of wire is connected to a `sen-sitive` point in the oscillator circuit. Any object in the vicinity of this wire will load and detune the oscillator; the extent to which this occurs depends on the size of the object, how `lossy` it is, how close it is to the wire, and, of course, how stable the oscillator is.