Dual/Double or same polarity for festoon lights

Thread Starter


Joined Aug 26, 2018
Hi all,

What an amazing place and I'm sure one of you clever peoples will put me to shame here and give me a really simple response. Lets see.

So I have these festoon lights for my garden that I replaced the really poor power adapter/controller. Is had different settings to change the flashing sequence which I also didn't want - I just wanted them on solid. So once the new driver was added I found it only lite up every other bulb. Swapped the wires over and every other bulb would light up. So assume this is due to every other bulb being wired the other way around.

My question to you: Is there a nodule or something I can purchase that would send the same polarity down so all the bulbs illuminate and not just every other one?

Many thanks,



Joined Jul 18, 2013
Is there two feeds to each string? if so all you may have to do is reverse the origin so they have the same polarity.
Otherwise can you change over each alternate light connections on each light fitting?

Thread Starter


Joined Aug 26, 2018
Hi and thanks for the rapid responses which is awesome.

So I cannot rewire every-other light as they are sealed units. And it would take me forever.

The old PSU has the below details on it so assume it's AC:
Model no: T44BS 24v 9w
Input: 100-240v 50/60Hz Max 38mA
Output: 24v 9W Max 0.38A

It has a little button it it where you can change the lights from Waves, sequential, flashing or always on etc. It's the always on setting I want and the only way I can see how this PSU does that is by sending down the 2 wires it has going to the lights is by sending down both polarities down both cables. I didn't even know that was possible lol.

Thanks again for the responses guys. :)



Joined Jun 22, 2012
It uses "Pulsed DC" to put all the leds on, as they are wired back to back in series, so every other led is on on each cycle, if you use static DC only one set of leds will be lit.

You circuit uses four transistors in a bridge formation to switch the leds on/off.

As i suggested earlier, use an AC supply.