A pneumatic compressor capable of supplying compressed gas to a pneumatic tool. The compressor can be powered alternatively by either a battery or an AC power source. The compressor comprises a permanent magnet DC electric motor and circuitry for converting the AC power source to DC power. The compressor includes a receptacle for accommodating one or more of a plurality of batteries and includes circuitry for using batteries having different voltages. The AC power source may also be used to charge a battery connected to the compressor.