The present circuit serves for the transmission of information signals over the general electricity supply mains. It has a transducer (13) for the galvanic separation of the mains voltage. The mains side winding (L1) of the transducer is connected in series with a capacitor (C1) in order to separate...http://www.google.se/patents/US6671501?utm_source=gb-gplus-sharePatent US6671501 - Signal transmission circuit
