A multi-voltage A.C. and D.C. power supply comprising: a power supply module having an A. C. power input, at least one A. C. power output, at least one D.C. power output, and having an incoming power output selection signal; a sine wave synthesizer within said module having a D.C. power input, a synthesized A.C. power output, and having as input one or more sine wave synthesizing control signals; a first connection between the module's A.C. power input and the synthesizer's D.C. power input, said first connection comprising a first rectifier; a second connection between the synthesizer's A.C. power output and the module's A.C. power output; a third connection between the synthesizer's A.C. power output and the module's D.C. power output, said third connection comprising a second rectifier; and characterised by: a control system adapted to receive measurements of voltages at the module's A.C. and D.C. power outputs (446, 442) and currents at A.C. and D.C. outputs (448, 444), and also to receive the module's A.C. or D.C. power output selection signal, the control system is further adapted to generate the sine wave synthesizing control signals and adjust the sine wave synthesizing control signals to regulate whichever output signal, A.C. or D.C., is selected via the power output selection signal, so as to maintain the selected output signal (407, 409) at a predetermined A.C. or D.C. preset voltage level. a power supply module having an A. C. power input, at least one A. C. power output, at least one D.C. power output, and having an incoming power output selection signal; a sine wave synthesizer within said module having a D.C. power input, a synthesized A.C. power output, and having as input one or more sine wave synthesizing control signals; a first connection between the module's A.C. power input and the synthesizer's D.C. power input, said first connection comprising a first rectifier; a second connection between the synthesizer's A.C. power output and the module's A.C. power output; a third connection between the synthesizer's A.C. power output and the module's D.C. power output, said third connection comprising a second rectifier; and characterised by: a control system adapted to receive measurements of voltages at the module's A.C. and D.C. power outputs (446, 442) and currents at A.C. and D.C. outputs (448, 444), and also to receive the module's A.C. or D.C. power output selection signal, the control system is further adapted to generate the sine wave synthesizing control signals and adjust the sine wave synthesizing control signals to regulate whichever output signal, A.C. or D.C., is selected via the power output selection signal, so as to maintain the selected output signal (407, 409) at a predetermined A.C. or D.C. preset voltage level. a control system adapted to receive measurements of voltages at the module's A.C. and D.C. power outputs (446, 442) and currents at A.C. and D.C. outputs (448, 444), and also to receive the module's A.C. or D.C. power output selection signal, the control system is further adapted to generate the sine wave synthesizing control signals and adjust the sine wave synthesizing control signals to regulate whichever output signal, A.C. or D.C., is selected via the power output selection signal, so as to maintain the selected output signal (407, 409) at a predetermined A.C. or D.C. preset voltage level.