Abstract: An electric fence controller for controlling the charge on an electrified fence. A charging circuit is provided which includes a ferro-resonant input transformer. The transformer is provided with primary and secondary windings wound on separate legs of a saturable core. A capacitor is connected across the secondary winding and forms a resonant circuit with the secondary winding. An energy storing capacitive circuit is connected to the charging circuit. A voltage multiplying output circuit is connected to the capacitive circuit through a switching circuit. This arrangement enables the input to the transformer to be electrically isolated from the output circuit.