To control the operation of a piezoelectric relay, control circuitry is disclosed for direct ohmic connection to a utility AC source to draw the minimal power required to actuate the relay's bimorph member pursuant to selectively switching power current through either one of two separate loads. The control...http://www.google.de/patents/US4658154?utm_source=gb-gplus-sharePatent US4658154 - Piezoelectric relay switching circuit
