A circuit for controlling a valve assembly in applications where electrical isolation of the two control signal supply lines is required to prevent damage of control circuits caused by a reverse polarity feedback signal or other transient signal. The circuit includes a solenoid having a coil. The coil has a first end and a second end. The circuit also includes a first switching circuit electrically connected to the first and second ends of the coil to allow current to pass therethrough in a first direction to move a permanent magnet against a pushpin a first axial direction. The circuit further includes a second switching circuit electrically connected to the first and second ends of the coil to allow a current to pass therethrough in a second direction to move the permanent magnet away from the pushpin in a second axial direction. Further, when either switching circuit is allowing current to flow through the coil, it electrically isolates one negative control source from the other. The use of a pair of switching circuits electrically connected to the coil results in a relatively low voltage drop across the circuit.