Traditionally Christmas lights were always AC powered using either direct connection to the main (240V) or via a small plug pack power supply.\u00a0 One of the many queries I get is should we go AC or DC for lighting Control.\u00a0 Let’s explore this point further.<\/p>\n
For the Purposes of this discussion we will break the type of lights into 2 main categories Low Voltage<\/em><\/strong> and High Voltage<\/em><\/strong>.\u00a0 Low voltage Lights are any lights, AC or DC, that are connected to a transformer of sorts like a plug pack.\u00a0 the majority of Christmas lights\u00a0 fall into this category.\u00a0 High Voltage lights are any lights that connect and operate directly from 240v Mains.\u00a0 Rope lights are the most popular version of this category<\/p>\n To control lights in a display that both you and your audience enjoy,\u00a0 Safety is paramount.\u00a0 Here is Australia, using mini globes direct connected to mains it not allowed in external displays (for some unknown reason the authorities are still willing to allow people to use them inside where the risk is still high).<\/p>\n A couple of people have tried unsuccessfully to control their low voltage lights by switching the mains voltage.\u00a0 the results were a complete melt down of the plug packs.\u00a0 but hey, step down transformers were never intended to operate on chopped mains.<\/p>\n High voltage<\/em><\/strong> lights can still be used in Australia as long as there is adequate protection.\u00a0 I still use rope light in my display due to the strong mechanical characteristics and the the solid colours.\u00a0 With careful technique the lights can be trimmed to length for suit each display item.\u00a0\u00a0 High Voltage lights require AC Dimmers for control.\u00a0 My 16ch AC Serial SSR is but one example of such dimmers.\u00a0 Available in 24, 36, 48 Vac, they dim lights by chopping the AC voltage supplied to the lights.<\/p>\n Low voltage<\/em><\/strong> lights rely on some form of step down transformer to provide isolation\u00a0 protection form mains voltages.\u00a0 Typical incandescent mini globe type lights are an example.\u00a0 these lights are usually AC.\u00a0 However to dim these lights the dimmer needs to be placed between the plug pack and the lights.\u00a0 (You can not dim the mains going into the plug pack – this is not only dangerous but could result in a fire!)\u00a0 My 16ch AC Serial SSR is but one example of such dimmers.\u00a0 Available in 24, 36, 48 Vac, they dim lights by chopping the AC voltage supplied to the lights.<\/p>\n LEDs also fall into the Low voltage<\/em><\/strong> category.\u00a0 However LEDs are a “current” device, meaning the way to dim them is by varying the current and not the average voltage like a incandescent mini globe.\u00a0 LEDs as best controlled using a constant voltage that is chopped on and off.\u00a0 By turning the light on and off quickly enough, we trick the eye into thinking a dimmed LED is actually ON all the time.\u00a0 So here is a simple test you can do at home.\u00a0 There are no tools required.\u00a0 I said at home, but I real meant in your car.\u00a0 The occurrence of LED stop lights and blinkers in cars today has dramatically increased over recent time.\u00a0 Next time your in your car, see if you can notice if the lights in front are LEDs of not.\u00a0 You can tell by the bright constant light and sometimes the individual lights. Now for the real interesting observation: see if you can notice LEDs turn off in an instant, where and incandescent globes just , well fade away.\u00a0 It is very noticeable.\u00a0 This reminds me of my grand mother who once said how amazing it is that when she flicks the switch the light instantly comes on.\u00a0 Well we now know that is simply not true, it is not instant\u00a0 there is a finite delay.\u00a0 I wish she was still alive to be able to amaze her again.<\/p>\n So back to the point at hand.\u00a0 AC or DC.\u00a0 Well the real only is that depends on your load.\u00a0 If you are using Mains lights, AC is definitely the way to go.\u00a0 If you are using low voltage, I would say you can<\/em> use AC for Minis, an DC for LEDs.\u00a0 But you can<\/em> also you can also use DC for them both too.\u00a0 That is what I do.\u00a0 AC for mains lights and DC for the rest.\u00a0 It keeps things simple.<\/p>\n The other reasons I like DC for my low voltage stuff is SMPS are:<\/p>\n Have a good one!<\/p>\n","protected":false},"excerpt":{"rendered":" Traditionally Christmas lights were always AC powered using either direct connection to the main (240V) or via a small plug pack power supply.\u00a0 One of the many queries I get is should we go AC or DC for lighting Control.\u00a0 … Continue reading \n