So my system needs 120 V and 12 V. And I'm trying to avoid having 2 input plugs for my system.

Thus, I'm looking for a dual power supply that splits 120 V input (wall plug) into 120 V and 12 V.

Are there any dual power supply that splits input voltage to 120 V and 12 V?

If there is no such a thing, how could I feed my 120 V system and 12 V system with one input plug?

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    \$\begingroup\$ Do you need 120 V AC and 12 V DC or some other combination? If it's 120 V AC and 12 V AC, you could just use a transformer perhaps. Otherwise, everything I can think of boils down to having a 12 V power supply feeding from the 120 V. \$\endgroup\$ – AndrejaKo Jun 21 '13 at 13:15
  • \$\begingroup\$ im sorry, its 120 V AC and 12 V DC \$\endgroup\$ – Tony Yi Jun 21 '13 at 13:58
  • \$\begingroup\$ Are you in a country with 120 V mains? \$\endgroup\$ – The Photon Jun 21 '13 at 15:31

You don't need one power supply that does both. Two power supplies, each providing what you need, connected to the input power in parallel will do what you need.

If you want only one cord to your device, look for power supplies that can be mounted internally.

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  • \$\begingroup\$ how would i connect them in parallel? sorry, im a beginner. they are 120 V AC and 12 V DC by the way... and thanks alot \$\endgroup\$ – Tony Yi Jun 21 '13 at 14:01
  • \$\begingroup\$ @TonyYi is 120VAC not what's supplied by the electric utility in your area? \$\endgroup\$ – Phil Frost Jun 21 '13 at 14:05
  • \$\begingroup\$ yes phil, they are. i just need to be able to control 120 v ac system with arduino. \$\endgroup\$ – Tony Yi Jun 21 '13 at 14:12
  • \$\begingroup\$ @TonyYi well then, someone else has already built one of your power supplies, and you just need 12V. This isn't any different from plugging a 12V adapter into the wall, except if you want one cord, you do the connection inside your device. You probably also want a fuse, and a better understanding of electricity so you don't harm yourself with the 120VAC system. \$\endgroup\$ – Phil Frost Jun 21 '13 at 14:15

I would never recommend working directly with mains electricity unless you really know what you are doing. The following is for information. You can purchase a transformer with two secondary windings. From this you can develop a suitable power supply.

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