Proposed is a device actuated by a transponder for the generation of a switch signal. The device is based on an oscillating circuit (10) with a capacitance (C.sub.1), an identification coil (L.sub.1) and an oscillator amplifier (12). Connected to the oscillating circuit (10) is a frequency observer (20) which evaluates the frequency (f.sub.1) tuned in the oscillating circuit (10) and which when finding a change emits a switch signal (S). A change of the frequency in the oscillating circuit (10) is effected by the approach of a transponder (60). The device permits a nearly loadless transponder identification.