Power Supply Question

[duggerd]

I was wondering for a project what I could use to power a RFID reader at 12 V DC at 20 mA? Is there a power supply I could build to create this?

[ivan747]

Are you powering these from batteries?

[duggerd]

No I wanted to power it from a 12 V 0.15 A wall wart.

[Kiriakos-GR]

You will probably need something small but stabilized .

Search for 12V stabilized power supply at 500mA , I do not think that you will find smaller than that.
They have small transformer inside and they do the job.
They cost 5-6$ .
 

[duggerd]

This is what I want to power. http://cgi.ebay.com/New-Design-Wiegand26-RFID-Reader-125KHz-Bell-/130411597050

[ivan747]

Easy, get one of these: http://www.sparkfun.com/products/9442

It will do the job perfectly.

[duggerd]

Doesn't the output have to be 20 mA?

[Kiriakos-GR]

Doesn't the output have to be 20 mA?

This is what your device needs to get, what the PSU can deliver its another story.

[duggerd]

Is there anything I can to build that takes 12V at a higher mA, and brings it down to 12V at 20mA?

[nyo]

Duggerd,
Your RFID reader draws 20 mA, the ones suggested here are capable of supplying 500 mA and 600 mA. As long as the voltage is right, these will work, your device will only draw the necessary current from those, 20 mA.
You can connect any 12V device to these as long as it uses less then 500 and 600 mA