minature transformers wanted

[jack0987]

I have a small project that needs both 5vdc and 12vdc.
I have a dual voltage power supply but it is way to big to fit in the box.
I can get a 5vdc usb charger that is about 1 inch square easy enough,
but finding a 12vdc one about the same size is not so easy.

So, just build a little one perhaps?
Finding a very small transformers for a dollar or two
with a 120vac input and outputs of about 7vac and 15vac is proving not to be so easy either.
Yes, there are deals out there, but will I be able to get another one 6 months from now and
another one a year from now.

Anyone know of any?
For lack of a better idea at this time,
miniature transformers wanted.

 

[ronsimpson]

A 5VDC USB power supply probably makes more power than you need. I would use a PWM IC to boost the 5V to 12V. In my case I would build it but here is one built.
Boost Supply $6 (that's 3 supplies for $6)

Here is another one. Have not looked at it. link

 

[ronsimpson]

Or a very different way.
Get a 120Vac to 12Vdc supply and then add a small 12V to 5V buck power supply. (looks much like the above supply, but works differently)

 

[dr pepper]

You can get leads, a usb connector one end with a 5v to 12v inverter inside, and a dc barrel jack at t'other, a little doctoring would give you a 12v and a 5v o/p.

 

[Pommie]

I'd go with the 12V wall wart and 5V regulator. What current is required?

Mike.

 

[jack0987]

Thanks for the replies.

I'd go with the 12V wall wart and 5V regulator. What current is required?

Mike.

Not much current is needed. At present, I think I'd go your way. Thanks, Mike.

 

[rjenkinsgb]

Look at a Meanwell IRM-03 12V
That's a tiny encapsulated PSU that gives 12V at up to 3W from AC mains (world standard).

Add either a switching or linear 5V regulator and you have both supplies.

And they are cheap! https://uk.farnell.com/mean-well/irm-03-12/power-supply-ac-dc-12v-0-25a/dp/2815483

 

[jack0987]

Look at a Meanwell IRM-03 12V
That's a tiny encapsulated PSU that gives 12V at up to 3W from AC mains (world standard).

Add either a switching or linear 5V regulator and you have both supplies.

And they are cheap! https://uk.farnell.com/mean-well/irm-03-12/power-supply-ac-dc-12v-0-25a/dp/2815483

Thanks. I like this idea. Meanwell also makes a 5vdc version.
Thinking I can use one of each and just connect the grounds together.
Does that seem workable?

 

[rjenkinsgb]

Thanks. I like this idea. Meanwell also makes a 5vdc version.
Thinking I can use one of each and just connect the grounds together.
Does that seem workable?

Yes, certainly - that would work fine.
The only reason for suggesting a 5V regulator with the 12V one was to save cost and space, if the power requirements were low enough.

 

[jack0987]

Yes, certainly - that would work fine.
The only reason for suggesting a 5V regulator with the 12V one was to save cost and space, if the power requirements were low enough.

These are working great for me. Found out, they also make a 3.3vdc version which will work even better.
They make other voltages as well.