A low field magnet system is described which is suitable for optical and magnetic resonance experiments. It consists of three pairs of orthogonal Helmholtz coils, whose currents are controlled by a microcomputer to provide a magnetic field with a specific field and direction. Earth’s field compensation is programmed. The field magnitude is accurate to 0.1 G and direction to 0.3 deg for fields greater than 5 G. The maximum field is 50 G.