Fluorescent tube lights might not be the most efficient bulbs you can buy, but they are still really clever feats of engineering.
The way they work is that a current passes through the sealed gas tube, which excites the mercury vapor and triggers UV light that causes the phosphor coating inside the tube to glow.
To get that initial burst of current to trigger the mercury, it needs a boost of current provided by a choke, which also lowers the current when required.
But what about LED tube lights – do they need the same choke?
LED tube lights don’t need a choke, but they have a bit of technology called a driver. LED drivers alternate higher voltage AC current to the necessary low voltage DC current for the bulb and protect it from fluctuations.
To help you understand this in full, I’m going to explain to you:
- Why a choke is needed in fluorescent tubes
- Whether a choke and a ballast are the same thing
- Why a choke isn’t used in LED tube lights and what they use instead
What Is The Function Of Choke In Fluorescent Tubes?
A choke has two purposes in a fluorescent tube, although both involve regulating the current.
Firstly, it has the vital job of giving the current a boost when the light is first switched on.
That initial spike is necessary to trigger ionization in the tube when the mercury atoms in the vapor excite and emit ultraviolet light.
Once that ignition is achieved and the tube begins to glow, the second function of the choke kicks in, which is where it limits the current.
After the bulb is illuminated, it doesn’t need the same high level of power running through it, and it could actually be unsafe.
The reason it’s unsafe is that once it’s ionized, the gas has negative resistance.
Because it has negative resistance, the unchecked current will continue increasing as it flows through the tube.
Eventually, this will damage the lamp.
So the choke’s job is to lower the current and limit it to a safe level.
It’ll then keep the current relatively consistent until the circuit is opened by the switch being flicked to the off position.
It does that by design – a choke is a coil.
When the current passes through the coil, it generates a magnetic field, which then blocks most of the AC current from passing through, restricting it.
This property is called inductance.
Are Choke And Ballast The Same?
When you’re talking about a choke or a ballast in fluorescent tube lights and bulbs, they are different names for the same piece of technology.
Often they are referred to as a ballast choke to confuse matters even more.
Whether a choke or a ballast, they do the same thing – providing an initial spike to trigger the necessary reaction in the tube light before generating the magnetic field, which limits the current passing through.
The confusion isn’t helped by the fact that an ‘electronic choke’ can also mean different things in different fields, such as an electronic choke in a car.
All you need to know is that, when talking about CFL lighting, a choke and ballast are the same things.
Are Chokes Required For LED Tube Lights?
So now that we fully understand a choke or ballast for fluorescent lights do LED tubes need the same technology?
Well, the answer is sort of.
They don’t have a choke, but they have an LED driver, which does a similar job, but different.
LEDs don’t need that same spike to trigger a reaction.
The diodes need constant DC current, which needs to be controlled at a lower voltage to protect the light.
That’s the job of the LED driver. It acts as a DC power supply, converting the higher voltage AC current to the lower voltage DC that the LED needs.
So it is similar to a choke in that it regulates the current. Still, it’s technically a different sort of equipment.
Internal vs External Drivers
Most of the LED tube lights you’ll find in electrical stores have drivers built into the bulb. This makes it much easier to fit them into existing light fixtures – all you need to do is remove or bypass the existing ballast.
However, it does negatively impact the quality of the bulb.
That’s because the driver parts have to be smaller to fit inside, which makes them less efficient.
It also increases the heat inside the bulb, which over time, will reduce the lifespan of the diodes.
If you search for LED tube lights with external drivers, they’re easy enough to find, but you’ll need to install the driver into the fixture or circuit, which can be much more work.
The benefits are a more reliable driver which can better regulate the current, giving your LED tube light the longest lifespan possible.
LED tubes with internal drivers will already nearly double the lifespan compared to fluorescent tubes (from around 30,000 hours to 50,000), but if you want the most efficient lighting system, paying extra to upgrade to an external driver system will serve you better in the long run.
There is a third option. While LED tube lights work best with a driver, you can buy “plug-and-play” options designed to work with existing ballasts.
These are the easiest retrofitting option – swap the fluorescent tube for the LED one, and you’re good to go.
However, you will get a different reliability because LEDs should really use a driver. The ballast might burn out and is more likely to malfunction.
Upgrading the fixture with a dedicated driver designed for LEDs is the best choice if you want the full benefits of long-lasting, energy-efficient LEDs.
I said at the start that fluorescent tubes are clever, and the chokes and ballasts used to make them work correctly and efficiently are also the results of some pretty brilliant engineering.
But they aren’t the right technology for LED tube lights.
LED drivers might do the same job as a choke, but they’re intended for use with LEDs and will keep the diodes lighting up for longer and make the lights as safe as they are meant to be.
If you’ve installed LED tube lights in your home or workplace, did you choose ones with internal or external drivers?
Are you considering the upgrade from fluorescent?