DC power supply

Sep 12, 2016 17 Replies

Thinking of using one of these temp sensor/displays:

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Would need a 30mA DC supply ... 12-24V



Anyone know of small low cost DC supply modules ? ..........



I have a draw full of psu's ... laptop, router etc, I could use one of those but as it only needs 30mA something small will be easier to house in an existing box.



I would suggest getting a small wall-wart supply, and feeding the

12V into your box via a 2.1mm power jack. These are much cheaper than modular mains power supplies for building into your own kit, and it means you don't need to bother with the mains side yourself.

An example:

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rick laid this down on his screen :

A pair of PP3 batteries in series would output 18 to 20v, just add a push button for when you need to read it.

My biggest problem in finding a PSU for this.

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Was obtaining a 9V supply that didn't involve a switching circuit as that just produced so much hash that it wiped out all AM frequencies.

Found one off an old DAB radio.

But it's still going to need a mains plug so why not use a 12v wall-wart?

But it's still going to need a mains plug so why not use a 12v wall-wart?

Simon Mason used his keyboard to write :

Lots on Ebay...

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They are rubbish - you need a transformer, not a switching PSU.

Tons of plug packs on ebay and amazon and aliexpress.

Be a great idea to test one for rfi though, its getting really hard to find one that does not double as a radio jammer. Brian

Then something like a simple module would be way to go ?

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sorry English is not my first language

I have several of those type .... have to whittle out the psu ones away from the charger ones

A cheap imported one off ebay - I wouldn't be surprised.

Go to a decent supplier.

Those are switch mode PSU's.

Some SMPSU's can be quite noisy, especially if your interest is HF. I use a very well filtered and expensive SMPSU as my shack supply, so it is do-able.

My outdoor high power led security lights are a bugger on HF as well.

I wouldn't!

I'd look in RS or Farnell for one that probably won't catch fire... (Too many BigClive.com videos).

But seriously, the OP will find something there - either a wall wart or a small PSU module.

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