Hey Guys,

I just need some help with basic electricity. This has nothing to do with a course but just something I am fixing up.

Basically I need to output 3.3V 1A and 5V 0.5A but have no idea how to do it. I have been out of touch with my electricity course for a long time now.

Say I bought something like this ---> http://www.ebay.ca/itm/MB102-Breadbo...t_5208w t_907

It gives me 3.3V and 5V but what about my current? Im a noob at this so any help would be greatly appreciated

I am thinking of just hunting around for power adapters that provide the above specs and then cut the ends of and splice the rest.

http://www.ebay.ca/itm/AC-110V-220V-...t_3366w t_907

http://www.ebay.ca/itm/3-3V-2-5A-AC-..._1395w t_1002

Thoughts?

Thanks
Rio

That supply module will have some kind of max current output listed in its specs maybe in its manual or something. It itself is going to be powered by a wall wart which will have some kind of max current out as well, so just thinking about it: Most wall warts are like 300mA - ~1A max output. If you needed to supply total 1.5 amps out of that module then I dont think it'll work for what you need it too. Mind you, this isnt rigorous calculation just a thought. Look up the specs of that board but im pretty sure it wont be powerful enough.

Originally Posted by jewfro9000

That supply module will have some kind of max current output listed in its specs maybe in its manual or something. It itself is going to be powered by a wall wart which will have some kind of max current out as well, so just thinking about it: Most wall warts are like 300mA - ~1A max output. If you needed to supply total 1.5 amps out of that module then I dont think it'll work for what you need it too. Mind you, this isnt rigorous calculation just a thought. Look up the specs of that board but im pretty sure it wont be powerful enough.

Yeah, thats what I thought but I couldn't find any information.

Guess Ill have to go with the power adapters >.>

Thanks

What are you using this for?
1 A is going to fry just about any standard voltage/current regulator. The arduino power supply on the ebay link is unlikely to power more than 100mA consistently, with peaks no more than 300mA. You get more if you use the wall socket over the usb input but still, 1 A is huge. Better to stick with specific supplies rated at this voltage.

Also if you plan on purchasing a higher voltage source and then branching off that source to create a "second" source of lower voltage then use a voltage regulator. Ive seen people attempt to use resistors and diodes to do this. It will always fail (particularly using resistors)

Originally Posted by qwerty91

What are you using this for?
1 A is going to fry just about any standard voltage/current regulator. The arduino power supply on the ebay link is unlikely to power more than 100mA consistently, with peaks no more than 300mA. You get more if you use the wall socket over the usb input but still, 1 A is huge. Better to stick with specific supplies rated at this voltage.

Also if you plan on purchasing a higher voltage source and then branching off that source to create a "second" source of lower voltage then use a voltage regulator. Ive seen people attempt to use resistors and diodes to do this. It will always fail (particularly using resistors)

I was planning on using 2 separate voltage sources or like you said use a voltage regulator.

I found an old Airport Express which doesn't work anymore because the power supply died. Read a few online post showing their own way of fixing it. So now I am attempting to solve it another way/cheaper solution.


EDIT: Apparently iFit it has a step by step tutorial and provide a kit to fix it for 20$ lol. Might go this route.

http://www.ifixit.com/Guide/Installi...ply-Kit/7090/1

I looked at the iFitIt kit and from what I can gather the parts if bought on your own should be in the $3-4 range plus the cost of a 5V/1.5A power supply ($5-6). Always gets parts from DigiKey. They are using a simple voltage regulator, the National LM317AT. It outputs a max of 1.5A and has an adjustable voltage output. The resistors they are using suggests they are regulating between 3.3 and 5 V. I should be able to figure out the circuit from the pictures plus they have also specified the resistor and capacitor values. I highly recommend getting these parts and making the circuit on your own. Let me know if you have any other questions.

Originally Posted by pavlov

I looked at the iFitIt kit and from what I can gather the parts if bought on your own should be in the $3-4 range plus the cost of a 5V/1.5A power supply ($5-6). Always gets parts from DigiKey. They are using a simple voltage regulator, the National LM317AT. It outputs a max of 1.5A and has an adjustable voltage output. The resistors they are using suggests they are regulating between 3.3 and 5 V. I should be able to figure out the circuit from the pictures plus they have also specified the resistor and capacitor values. I highly recommend getting these parts and making the circuit on your own. Let me know if you have any other questions.

Awesome thanks! I wanted to buy the parts myself but had no idea where to get them from. Will look for the rest on there, will order them and come back.

Thanks