Abstract: An inductive coupler (1) comprises a rectifier (2) to rectify an input alternating current power supply, a high frequency oscillator (3) driven by the rectified power supply, a modulator (4) to modulate the output of the high frequency oscillator (3) with a lower frequency alternating signal, a split transformer (6) having physically separable primary and secondary sections, and a demodulator (7). The output of the modulator (4) is coupled to the primary section of the transformer (6), and the secondary section of the transformer (6) is coupled to the demodulator (7) which demodulates the modulated high frequency signal to produce a low frequency power output. An auxiliary connector (8) connects a reference from the low frequency modulation signal imposed by the modulator (4) to the demodulator (7) to maintain synchronism.