use of leds

I'd consider a series resistor.  5V may work, but it might be a bit much for the LED's, impossible to say without actually seeing how the barn is wired.

I'm pretty surprised it uses an AC adapter, are you sure of that?

Gunrunnerjohn,

Thanks for replying. The only instruction is wording on the box that says to use a 4.5 v ac adaptor. The barn has an outside jack for plugging in a power source like you normally see on an ac adaptor. I called Radio Shack and they said I needed to know for the amps of the bulb before buying a 4.5 ac adator, which I don't know unless I try to contact the manufacturer. It looks like there is a resistor in the wiring when I look inside the barn. I have wired other leds on my layout just by connecting them to my other lighting at 9 or 10v. I suppose I could rewire the barn avoiding the plug in.

John Henry

Hard to say, I'd try a 5V regulated DC adapter with a 100 ohm resistor in series and see how that does.  If it doesn't light, reverse the polarity of the supply and try again.

thanks, I'll give it a try

The term "AC adapter" frequently means it plugs into an AC outlet...thereby adapting the device to AC operation (as opposed to battery or DC operation).  So an AC adapter can have DC output.   And I suppose one could call a DC-output cell-phone charger an "AC adapter".

thanks for the replies, as suggested by banjoflyer, find an old adapter if possible. I found the correct plug from 1 old adapter (I save everything) and wired it to another old adapter which was the right voltage but the wrong size plug. My barn lights and I am a happy man.

Thanks,

John Henry

Note that the adapter posted by Mark is an AC-DC adapter, the output is 4.5V DC, not AC.

You will want a regulated wall wart, the unregulated ones have much higher output voltages at anything less than their rated load.