- So today we're going to be looking at cheap LED strip,
something he likes to call cheap LED tape,
and I've got a feeling that's going to fall apart today.
So Gordon, talk us through what we're gonna look at.
- Okay, Gary.
So I've been on a well known online retailer
and bought some LED tape
that came with free next day delivery.
- [Gary] Okay.
So I've picked it up.
There is not a lot of resources gone into there
from the Earth's crust, is there?
That is a very, very light LED strip.
So what are you gonna prove to us then?
- Okay. So we're going to look at,
sometimes what's known as constant voltage LED tape
and compare that
to something that's known as current regulators.
- Okay. And we've got both in front of us here.
- Yeah.
We're gonna look at the very economically priced one first.
- Okay.
- And then compare how it performs
when you start looking at things like input voltage
and voltage drop across the tape.
- Okay. Alright.
And see how that affects perhaps the light output, yeah?
- Yeah.
- Okay then.
So are we going to power this one up first?
Is that the idea?
- So we're going to power it up.
- [Gary] Okay, so that is a 12 volt LED strip.
- It is. Yep.
- And it's five meters long.
- [Gordon] It's five meters long.
And the packaging claims that it's 18 Watts
but if I look at a power supply, there's the first problem.
It's actually 12 Watts.
- [Gary] Okay.
- So someone's been telling a few porkys there
or they may have made an improvement in the LED efficiency.
- Okay. Right.
So you're now going for what used to be,
I think a container for the chocolate treats.
- In the lighting industry,
you'd call this an integrating sphere.
So we've made our own one there.
I'm going to put that over there.
I'm gonna bring in our lux meter.
- And drill a hole in the bottom of it
because he kept taking the actual chocolates out the top
and getting there with his hand in there.
So okay.
So we're gonna use this to measure the light levels
and we measure it which SI unit?
- Yeah, we're using the Lux so this is not scientific.
This is just for comparison and what we have to hand here.
So it's just to do a comparative measurement.
So I'm going to put that on there.
- [Gary] Right.
And so we've got roughly 12 volts going down our LED strip.
We're doing it in the very starting point of the strip.
And you're telling me how many lux we got approximately.
- [Gordon] So there's about 1500 there.
- [Gary] 1500 lux. Okay.
- [Gordon] So that's it.
Bang on 12 volts on the power supply.
So I'm just gonna start dialing that back and you'll see,
- So you're going to drop the voltage now.
- Dropping the voltage,
- Okay.
- And you see immediately the light output is dropping down.
- What's the Lux level doing?
- [Gordon] So if I take that to 11 and a half volts,
- [Gary] So just half a volt.
- Half a volt off, it's now down at 1300-ish.
- [Gary] So we've lost 200.
- [Gordon] Yeah. Straight away.
- Just with half a volt.
- With half a volt, yeah.
- My issue there is that actually you're measuring that
at the very start of the actual LED strip.
Won't the strip naturally drop voltage
because of obviously its length and its resistance
as it gets towards the end.
- Yeah.
So let's have a look at that.
- Okay.
- So if I just
- Are gonna wind that up to 12?
- Wind that back up to 12 volts.
- And we've got about 1300 Lux at this stage.
It'll be really interesting to see
what lux we get at the end of the table
or further down the table.
I don't know whether they're gonna unravel all five meters.
So do you want me to unravel?
- So you unravel Gary, we'll do the technical bit.
- Yeah. I'm all over it. So that's a good couple of meters.
- Yeah. Well, five minutes.
- Do you wanna carry on?
- Okay so,
there's not a lot to it is there?
- Yeah.
- Okay, you wanna pull that off?
- So we've got that there.
- You don't want that out the way?
From my days at college,
I would presume that
there's going to be some volt drop here.
Maybe you're going to prove
that it's going to affect the actual lux output.
Okay.
- So there you go.
- Wow.
- Around about 700 lux so a massive difference.
- [Gary] So we had 1300 at 12 volts at the start.
- Yeah.
- Five meters further down at the very end,
we've got seven, seven and a half-ish.
- Yeah.
And then obviously now
if a factor in the volt was to drop again,
I'll go back down to about 11 volts.
I mean the human eye won't really pick up.
So that's now a six. 650 ish.
- [Gary] Wow.
- Yeah. So the human eye, won't pick it up.
However,
if you look at actually what's going on in this circuit
and here's a famous sketch I did earlier.
- LS lousy comes back again. Yes.
We've had this before with your prototype behind us
for the (mumbles) Cycle.
So yeah, you're back in with your cardboard
and your felt so just talk through this.
- [Gordon] So these are essentially,
if you think about it as your bus bar,
that runs along the LED tape.
So that's five meters worth
and that's carrying the whole current for each rank.
And then every, between each cut point,
you've got a little series connected chain of LEDs.
- They're LED emitting diodes.
So they LEDs? Light emitting diodes.
I think that's where your LED unravels. Doesn't it?
Cause they're actually LEDs.
Okay. So we've got a resistor,
we have three LEDs
and then we're connecting it back to our negative.
- [Gordon] Yeah.
- But as we go down the track,
obviously volt drop on the track itself
means we're not going to have the same voltage at the end.
- Yeah.
So the resistor will have been set
to get the correct current at 12 volts.
- Yes.
- And set.
But as soon as your voltage moves from 12 volts
- [Gary] Yeah.
- [Gordon] The current will alter
because that resistance is a fixed.
It can't do anything about it.
- Okay, fixed value of resistance.
The voltage change, we know Ohms law,
obviously the current will change.
- Yeah.
- Okay.
- So what happens in our tech here?
So obviously the LEDs at this end of the tent or running a
much higher current.
- Cause they're sucking all those voltage.
- Yep, than the ones at the far end of the, of the tab.
- And we saw that in deluxe level drop between the start and
finish.
And it correlates exactly the same
with the voltage change as well.
- So over a long period of time,
they're running brighter and hotter for longer than the ones
at that end.
So they're going to dim quicker
than the ones at the far end.
(speaks indistinct)
Wow. There's a lot to consider there.
Just in a reasonably price piece of LED strip,
actually the old saying you probably get what you paid for.
- Yeah.
So let's next.
Look at what happens on a one that has current regulation in
each one of these series chains.
- Okay.
So we've moved aside.
Our reasonably price LED strip on brought some OSRAM strip
and it looks identical almost to me.
What are you gonna try and prove to me now, Gordon.
- [Gordon] Okay.
So we're going to look at again,
look at what those components actually do.
First thing,
you'll notice that I said this tip isn't quite as flexible
as our very competitively priced one.
Cause there's that suggest more copper actually in the
circuit board. So we'd expect more copper,
less volt dropping.
- It makes sense.
- So I'm gonna power it up.
- Okay.
Now this is 24 volts. That's not an issue.
We're not worrying about being 12 on the first one,
24 on this one,
you're gonna prove to me at the start of the LED strip,
what the Lux levels are and whether that Lux level continues
throughout the strip.
That's really what we're trying to prove. Yes.
- Yes. And this is a lot higher power tabs.
So this, this entire strip is 67 Watts compared with our,
- 18.
That's actually 12 in the last one.
So I'll bring in our homemade.
- But that wasn't the issue we just want to see.
Is that the other way.
- So they all see we've got around about 7,000.
- [Gary] Yeah. So 7,000 looks at the very start that's okay.
You're in at 24 volts, you can drop the voltage.
- [Gordon] So I'll just wind that down so you can see,
it's not really moving now.
- So you've lost now about half a volt and it hasn't moved
really at all roundabout, half a volt.
But remember we started at 24. So you're coming down now.
Yeah. Closest to 23 again that's yeah.
7,000.
- [Gordon] Yeah.
- [Gary] Right. That's hardly moving at all.
- Yeah. So if you imagine that on that first example,
that moves straight away.
- And that bodes well to me thinking now,
and that goes back to 24 and you've dropped the voltage.
I would see we've kept the Lux. That will take the same.
I'm presuming the further down the LED strip.
I am that natural volt dropper.
Not going to really affect the actual output either.
- Yeah. Well, let's have a look at the end of the strip.
So if you will rappel it again. Okay.
You shouldn't really run the LED strip on a,
on a table, probably getting quite warm,
cause quite a bit of power in this strip.
- Okay. You want it all off. You're gonna go to the end.
Okay.
So it's whether it can remain at about just over 7,000,
is that what you're thinking? Yeah.
- Okay.
I'll bring it.
- Back up to 24 volts?
- So back at 24 volts.
This is getting quite hot
and then bring in there.
- You'll see.
Yeah.
- [Gordon] We're at 7,000.
- It looks a little higher.
- It is. Yeah.
It is actually higher at that end.
So again, I'll dial back the voltage.
- So that was that's that's yeah.
That's slightly higher than we had at the start.
And you bring the voltage down. That's not moving.
- Yeah.
- So how is that possible?
- So what we've got going on on this one,
so I'll bring in the number two.
I'll just switch that off a bit
because it's getting quite warm.
- Yeah.
- It's LS lounge. Number two,
we've got in this term six LEDs in series a and there's some
componentry on there. It's got more than
two legs on it.
- [Gary] Okay.
- [Gordon] So what we've got here
is a linear current regulator and
that senses the current flowing through that series chain of
LEDs and adjusts itself to make sure that current stays
constant.
- Ah,
so as the voltage could change this alters itself.
So almost like a variable resistor.
Is that sort of thing that it does it itself.
- Yes.
- And then therefore keeping the current constant throughout
those six LEDs.
- Yeah.
- Therefore we expecting to have
the same looks level when we measure it.
- Yeah. So let's just prove it by looking
at the voltage.
- Okay.
So that's good. So you're going to, yeah.
And then can we go back and do the reasonable price?
- (mumbles) which is the reasonably priced on.
- Okay.
So you're banking on-
- That's 20 volts anyway,
cause we're right next to the power supply.
- It's 23 actually, Gordon.
- Backup, just getting back to 24.
- So, hope we go to 24.
- So I expect it to be 24 at the end. Yeah.
It's bang on 24.
- Yeah.
- Bit of calibration, et cetera.
You're going to measure at the very start of the voltage.
(crosstalk)
- That's going to be 24.
- Okay.
So you (mumbles) straight at the end.
- And at the end.
And I'll power it up before I'll put the probes on before
blind myself.
- Okay.
- And then at the end of this strip here,
we're getting 22 and a half ish volts.
- [Gary] Okay.
- So there is a volt drop along the strip.
- Which we expect,
- But as we proved, the output of the LEDs
hasn't fallen off.
- Because it's got constant current.
- Yeah.
- Okay.
Well, that's good.
So again,
probably getting what you pay for?
- Getting what pay for.
So let's go back to our competitively priced.
- I've got a feeling we might run out of volts
when we get to the end.
Thanks.
So let's move that to one side and our competitively priced
one is just here.
So do you need to get fully unraveling?
- Yeah.
- It actually ends then.
So we've gone back to 12 volts and we gonna to see how many
of those volts you can get to the end of this very flimsy
LED strip.
- Very flexible though.
- Yeah flexible.
Very flexible.
Okay. Yeah.
Let's just pull them back, off.
- Okay.
So the 12 there.
And you can see what we get now. That is, yeah.
(speaks indistinct)
- Credibly flexible, is that the word you use?
Flexible.
Yeah.
Credibly flexible.
- Okay so.
- So that should be an easy one to measure.
So 12 volts on one end and at this end we've got right.
You can turn it on.
Let's see what we get.
- Yeah. So here about nine and a half volts.
- [Gary] Right.
Okay, now.
- We've lost a few on the way.
- Yeah.
And that's obviously a significantly lower power as well.
- Yeah.
- Which is why it's so flexible.
There's not much copper there.
- So let's summarize what we've proved there then.
So again, you get what you're paying for.
- Yeah. - Okay.
But actually the output from the,
what do you call the one on the Oz Ram,
it was a
- Current regulator
- Current regulator, meant that we got more
uniform light throughout the LED strip.
- Yeah.
Uniform for the entire length.
- And this one,
even though you reckon probably the eye isn't seeing it,
we're getting a considerably
different Lux level at each end.
- Yeah, So you won't see on day 1.
(laughs)
Well on day 101, 301,
you will start to notice.
It obviously depends on the application.
Interesting point to note is the packaging on this one
claims a life of 15,000 hours.
- (speaks indistinct) that's not long.
- No, but again, it depends on the application.
If it's in a wardrobe or a cupboard or something,
and you've got it on a switch to open every now and again,
you're not gonna notice that.
If you're running it in a corner,
in a room that's in use all day, if it's a shop
or a living room,
then that life can be actually quite short.
- And then you back, you're tearing in it out,
you replace it.
You (mumbles) hustle.
- Yeah.
- Okay as always, eFIXX would love to hear your comments on
installations you've done on LED strip something.
He still wants to call LED tape.
Even though I think we call them LEDs today,
that makes a lot of sense.
- Whatever.
- They're not LED. So as always,
please leave those comments below. And as always,
we're looking for your outstanding LED strip installations
and feel free to send them over to eFIXX.co.uk
where hopefully
we'll get to post them on our website for you as well.