Transformer Center Tap 110/220VAC to 18V AC 9V-0-9V AC, 500mA (0.5A), TMC USA
Center Tap AC TransformerInput AC Voltage: 120V / 240VOutput AC Voltage: 18V or 9V + 9V.Current: 500mA 0.5A maxFor 9V AC Output: use one blue and black wire (Don’t connect the 2 blue wires together or you will create a short circuit and damage the transformer!)For 18V AC Output: use two blue wiresWire Leads: 100% copper, 6.5″ long Width: 43mm (63mm with tab)Depth: 38mmHeight: 35mmNet Weight: 7.25 oz If you need DC voltage then you need a power supply not a transformer.If you try to measure the output using the DC setting in your multimeter, it will not give you a voltage.You need to set it to VAC in order to measure the output voltage.