120v to 24vdc and 5vdc

[cdnrookie]

Good evening guys,

I'm in need of a power supply (or 2) for a home project. I want to go from my 120v supply to 24vdc (1.5a) AND 5V DC (500MA)

I ACTUALLY ONLY NEED 3.3V DC, BUT FIGURE 5 IS EASIER TO ACHIEVE.

can anyone suggest a power supply or way of stepping down the 24vdc to 3.3vdc?

Ive seen a bunch of these power supplies on websites but would like to know of anyone that has tried the offshore brands or better yet offer up another solution

Thanks in advance

 

[danw]

A new or used 300watt ATX PC power supply will have 3.3V at 20amps.

The industrial world is full of 24Vdc power supplies. Take your pick.

 

[nhatsen]

If you only need 3.3Vdc, here are some options:

a) Use a cell phone adapter (5 Vdc) plus a 3.3V zener diode & resistor.
b) Use a voltage adapter or battery from 9Vdc to 15Vdc and a regulator like MAX748ACPA+.
c) Buy a ready-to-use 3.3V power supply like VOF-5-3.3, by CUI Inc.

 

[jrwb4gbm]

+1 for what danw said.
You should be able to salvage a power supply from an older (not too old) desktop computer. They have 3.3v , 5v, and 12v outputs. You can probably find one at a yard sale, flea market, or thrown on the curb.

 

[JordanCClark]

A few options from Allied Electronics.

Although I usually pick up a 24VDC Power Supply from EZAutomaiton, then use a buck converter from Ebay.

This one shows with a meter and has terminal blocks for wiring, but there are others without them that will get you down to the under-$1.50 per piece range. Adjustable from 3-30VDC @ 3A.

 

[Aabeck]

A cheap way to get 5 volts is buy a USB hub external power AC adapter.

100 to 250 VAC input, 5 VDC regulated output, and most put out 500mA to 1A, some higher.

 

[RussB]

I currently have in use a couple of old desktop power supplies which are very cheap at most used computer dealers.

 

[JeremyM]

OP: Do you require a regulated supply?

 

[geniusintraining]

Why not just use a 120-24vdc transformer then just use a resistor for 24 to 5, I do it all the time and it works good

 

[boneless]

Home project, I have used old phone chargers a lot. For costumers, we have used these Vicor converters:

http://www.mouser.com/Power/DC-DC-Converters/Isolated-DC-DC-Converters/_/N-brwkv
http://www.vicorpower.com/dc-dc/isolated-regulated/dcm

Very nice product, but not cheap.

 

[Helliana]

I have used the ATX powersupply route and it works quite well for 12V applications. All that you have to do is ground the PS_ON pin, which is usually a green wire.

I *THINK* the powersupplys also have a -12V signal, so you can go from +12V to -12V and get a 24Volt supply. I don't have a power supply nearby to test this though.

 

[OkiePC]

I *THINK* the powersupplys also have a -12V signal, so you can go from +12V to -12V and get a 24Volt supply. I don't have a power supply nearby to test this though.

I was going to say the same thing, but it was a quite old supply I worked on that had both plus and minus twelve volts and I am pretty sure it did not have 3.3v. There was 24 volts potential between the -12v and the +12v pins.

 

[jrwb4gbm]

I have used the ATX powersupply route and it works quite well for 12V applications. All that you have to do is ground the PS_ON pin, which is usually a green wire.
...................

The PS_ON pin is the (PG) pin shown in post #7. Just jumper between pin 7 and 8.

 

[automationtechie]

The DP-665 has outputs for 24 VDC and 5 VDC.

24V / 1.7A & 5V / 0.5A 65W Power Supply

http://www.icpdas-usa.com/dp_665.html