# Dual output AC/DC power supply **URL:** \ **Category:** Projects\ **Created:** [January 25, 2018, 9:46pm UTC](https://community.sparkfun.com/t/dual-output-ac-dc-power-supply/35198 "2018-01-25T21:46:40Z")\ **Posts on this page:** 4\ **Page:** 1
**Author:** ![MrZ2u](https://avatars.discourse-cdn.com/v4/letter/m/43a26b/32.png) [@MrZ2u](https://community.sparkfun.com/u/MrZ2u)\ **Post date:** [January 25, 2018, 9:46pm UTC](https://community.sparkfun.com/t/dual-output-ac-dc-power-supply/35198/1 "2018-01-25T21:46:40Z")
I am having trouble finding a powersupply to suit my needs. I am working on a more functional ATO or Automatic Top Off controller for an aquarium. The one you see here is a simple five volt relay board and the powersupply is an AC/DC making 5v/12v but only at 1a. Fine for the 5v side and in its present configuration on 12 as well. The pump I am presently using is not drawing but about 750ma max. I want to have it able to supply more amps to support a larger pump…while still remaining as small as possible. I can find plenty as big as a juice box but also with more amps than I might ever need…I figure 2a to 3a should suffice. Anyone seen any like that? …or, know how to make one from scratch? ![](https://canada1.discourse-cdn.com/sparkfun/original/2X/d/de840f31a29dad201f293e9ea0e0408da8311643.jpeg)[https://i.imgur.com/zuIrmfM.jpg](https://community.sparkfun.com/uploads/short-url/vKsVVqyImi3cbTZXeQZEutvnO1B.jpeg) ---
**Author:** ![n1ist](https://avatars.discourse-cdn.com/v4/letter/n/5daacb/32.png) [@n1ist](https://community.sparkfun.com/u/n1ist)\ **Post date:** [January 26, 2018, 12:27pm UTC](https://community.sparkfun.com/t/dual-output-ac-dc-power-supply/35198/2 "2018-01-26T12:27:47Z")
Two other ideas come to mind: - Use two power supplies - one for 5V and one for 12V. Tie their negative outputs together to the circuit ground, or keep them separate and use the 12v one only for the loads - Use one larger 12V supply and add a switching buck regulator to drop the 12v down to 5V. I would guess that your 5V requirements are quite low so you may even be able to get away with a linear regulator /mike ---
**Author:** ![MrZ2u](https://avatars.discourse-cdn.com/v4/letter/m/43a26b/32.png) [@MrZ2u](https://community.sparkfun.com/u/MrZ2u)\ **Post date:** [January 26, 2018, 3:10pm UTC](https://community.sparkfun.com/t/dual-output-ac-dc-power-supply/35198/3 "2018-01-26T15:10:05Z")
I neglected to mention the “later” part. This current set up is very manual. Plain old float switches to a relay and thats it. On/off with no intelligence. This is in a reef tank so there is a lot of motion so it does a lot of micro cycles each time it needs a top off. I am working on learning Arduino and the intent is to use optical fluid sensors and build in a buffer between cycles to prevent the aforementioned micro cycles. So, the arduino would power the relays and optical sensors just fine I believe but I still think I would need a dual output power supply wouldn’t I? This one might work but its external, I cannot tell its physical dimensions and I dont know if that 2a is shared or one and one. [https://www.sparkfun.com/products/11296](https://www.sparkfun.com/products/11296) ---
**Author:** ![MrZ2u](https://avatars.discourse-cdn.com/v4/letter/m/43a26b/32.png) [@MrZ2u](https://community.sparkfun.com/u/MrZ2u)\ **Post date:** [January 26, 2018, 3:11pm UTC](https://community.sparkfun.com/t/dual-output-ac-dc-power-supply/35198/4 "2018-01-26T15:11:32Z")
The one in the picture is this… [https://www.amazon.com/gp/product/B01EN … UTF8&psc=1](https://www.amazon.com/gp/product/B01EN0U8NG/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1) the description says “5V1A / 12V 1A” What determines the amperage of these and is it truly split or can it be shared?