This is a very useful unregulated power supply. Voltage is selectable by means of a positive click stop rotary knob on the front panel. DC as well as AC voltage is output from 2V - 12V in steps of 1 volts at 6 Amp. capacity. Safe and rugged power supply ideally suited for normal day to day use by students. Operates on 220/240V, 50/60Hz. Both AC & DC output voltages are overload & short circuit protected by thermal cutoff.