Switched Mode Power Supply with LEDs

[WIMorrison]

I just purchased a 12v 2A SMPS to run some LEDs and it pulses them off and on yet another one I use for powering some motors runs the LEDs correctly. This new one will also not power a DC motor.

 

I can’t return it as after I checked the output for 12v I cut the connector off to connect into the LED chocolate block

 

Any thoughts - other than throw it in the bin?

[amdaley]

Are you sure its a DC supply ?

[WIMorrison]

It shows the dc symbol on the output graphic and it shows as dc on the multimeter and nothing when I try it on AC therefore I am assuming it is DC

[Tricky Dicky]

It shows the dc symbol on the output graphic and it shows as dc on the multimeter and nothing when I try it on AC therefore I am assuming it is DC

Probably an unregulated PSU, you need to add a voltage regulator to the output. It is a simple circuit consisting of an IC and a few capacitors. Google will turn up a few if not PM me with a email address and I will send you a circuit. If using a voltage regulator make sure your PSU can deliver at least a 3V overhead over the desired output to your LEDs.

 

Richard

[Crosland]

It's a switch mode supply and will be regulated. An unregulated SMPS is a contradiction.

 

This kind of pulsing usually indicates an overload. The supply is shutting down and then trying again. I get it from an SMPS that I use to power a mini-drill if I over-do things.

 

What kind of LEDs and how many? Current limit resistors? Have you tried a single LED with a 2k resistor in series?

 

If the supply is designed for a specific purpose then it may require a minimum load. A general purpose SMPS should be stable with no load, which your multimeter suggests.

[WIMorrison]

I wondered if that is what it doing and checking the parameters of the lighting which are 24w (5m strip) and equates to 2A it would appear that the 2A supply is perhaps not 2A but slightly below

 

Hey HO, you live and learn