PROXIMITY SWITCH DEVICE

PURPOSE:To select the length of a signal transmission line optionally by providing a couple of oscillation electrode plates acting like an antenna outputting an oscillated signal from an oscillation circuit. CONSTITUTION:The oscillated output of a prescribed frequency is radiated from an oscillation circuit 5 through a couple of the oscillation electrodes 2, 3 and the electric force of lines are generated around the electrode plates. The electric line of forces at the outside of the electrode plate 3 and a detection electrode plate 1 located at the outside are changed in response to the change in the dielectric constant due to access of a human body. Thus, the electric field strength between the electrodes 1, 3 is changed, an induced voltage is generated in a detection coil 6 and extracted through an amplifier circuit 7. In this case, since the electrode plates 2, 3 act only like the antenna for the circuit 5, the length of the signal transmission line connecting a detection section comprising the electrode plates 1-3 and a control section comprising other circuits is adjusted optionally.