Position identification arrangement for object that is movable between two end positions e.g. motor vehicle locking bolt

摘要

The arrangement utilizes the moveable object to modify the oscillation in a self oscillatory circuit, which includes coils and an adjustment of a voltage supply. The arrangement includes an oscillating circuit (11) containing coils (L1,L2) which can be damped by the presence of the bolt (6). There is a transistor (Q1) for switching the voltage supply of the oscillating circuit on and off, under the control of a microprocessor (7). The working point of the transistor is adjusted using an output (9) of the microprocessor to provide switching hysteresis. The working point is automatically set, periodically, by increasing the voltage applied to the transistor, when the position of the bolt is known, until the oscillation state changes. The voltage is then reduced until the oscillation state just changes back again. An Independent claim is included for triggering the arrangement.