Patent ID: 7479791
Filing Date: 2009-01-20
Classification: H03K

Abstract:
1. A circuit arrangement for a capacitive proximity switch for the determination of an operating state and having: a capacitive sensor element, whose capacitance changes as a function of said operating state; a central capacitor; a first controllable connecting means which, as a function of a triggering signal, supplies a charging voltage to said capacitive sensor element; and a second controllable connecting means, which, as a function of said triggering signal, connects said capacitive sensor element to said central capacitor for a transfer of charge from said capacitive sensor element to said central capacitor, wherein said charging voltage is an AC voltage supplied from an AC voltage source and said AC voltage is supplied to said connecting means as the triggering signal in such a way that, in alternating manner, said first connecting means or said second connecting means is conductive.