This 9 watt, 500mA universal AC/DC power supply has an input of 120V AC 50Hz and a selectable 1.5, 3, 4.5, 6, 7.5, 9 and 12V DC output. It features a polarity switch and a 4 foot cord with the following connections:> 3.5mm OD / 1.3mm ID Barrel Connector 5mm OD / 2.1mm ID Barrel Connector 5.5mm OD / 2.5mm ID Barrel Connector 2.5mm DC Mono Connector 3.5mm DC Mono Connector 9v Battery Snap Connector IMPORTANT: WILL NOT WORK UNLESS POLARITY IS SET CORRECTLY. Polarity can usually be identified in your device's instruction manual and/or on the device itself. If you are unable to determine the polarity specification, please contact the manufacturer of the device you want to use this power adapter with. Please note: When testing this power adapter, you must test with a load as this is not a regulated power supply. The no-load voltage will be 1.5x higher than the selected voltage in order to have sufficient current output (this is due to the circuit inside, it is a diode bridge rectifier filter circuit, so the output voltage is higher than the specified voltage when testing without a load). Once the power adapter is connected to a device that is using power, the power adapter will provide the voltage you selected. If there is an issue, the capacitor storage may need to be discharged before showing the correct reading.
