Coupling circuit for e.g. power line, has capacitor connected in series with operational amplifier and primary circuit of transformer, and resistor with one terminal connected between output of operational amplifier and capacitor

摘要

The circuit has an operational amplifier (39), and a transformer whose a secondary circuit (43) is connected in parallel between a phase and a neutral on a low voltage network. A capacitor (40) is connected in series with the operational amplifier and a primary circuit (41) of the transformer. A resistor has one terminal connected between an output of the operational amplifier and the capacitor. An independent claim is also included for a remote meter reading system including an input interface.