LED brightness question

Joined
15 Jun 2021
Messages
2,406
Reaction score
589
Location
Wales
Country
United Kingdom
So if this forum can provide information about the difference the number of burnt out LED elements might be reduced
I think the responsibility we have is to ensure that a DIY'er has the correct power source for their LED's.

Using terms such as 'drivers' is partly irrelevant, given the general nature of the word.
For example:

Even if the technical term is a current driver; what really matters is whether a DIY'er requires a constant current, or a constant voltage supply - no ambiguity.

If we must always use the correct technical terms (even when the common term for them is drivers), then we quickly get into Winston's territory! ;)
 
Sponsored Links
Joined
7 Jul 2010
Messages
38,632
Reaction score
4,721
Location
Retired to:
Country
Portugal
Yes, it is just another example of a very common preexisting word being used for a new process and, as the previous meanings did not exclude the new usage, this new usage cannot exclude any subsequent uses.

Apart from that, the devices don't actually force - or drive - the current through the lights, do they?
They merely adjust the parameters so that the desired current is the unavoidable result. See Mr. Ohm.

So perhaps 'driver' isn't the right word for these devices anyway.
What about ' adjusters'?


Driver:
1656069941812.png


Similar to a myriad of other devices which have common words as names.
 
Joined
28 Jan 2011
Messages
51,076
Reaction score
3,507
Location
Buckinghamshire
Country
United Kingdom
Yes, it is just another example of a very common preexisting word being used for a new process and, as the previous meanings did not exclude the new usage, this new usage cannot exclude any subsequent uses.
Friday evening :)

I would personally say that, in the context of electronics, the word "driver" always has been (and probably always will be) a very general one which (as in the dictionary definition you have quoted) merely refers to something whose output was used as the input to something else. As such, there have been (and still are) any number of fairly diverse things which are reasonably described as "drivers".

The problem seems to be that some people have more recently got it into their heads that the word relates only to a very small subset of all the things it could mean - that's almost analogous to them deciding that the word "tool" now only relates to screwdrivers, or that "food" now only relates to sausages!

As with most of these sort of discussions, the important thing is surely that one should qualify the general term if one wants to refer specifically to a subset of its possible meanings?

Kind Regards, John
 
Sponsored Links
Joined
28 Jan 2011
Messages
51,076
Reaction score
3,507
Location
Buckinghamshire
Country
United Kingdom
The current through the individual LED elements is determined by the supply voltage and the series resistor, Therefore it requires a DC power source and NOT an LED driver,
A driver forces a current through the lights. It measures the current and automatically adjusts it's output voltage to be the voltage needed to drive the rated current through the LED elements,
Which results in the un-formed DIYer ( and some "professionals " ) connecting a driver ( current forcing ) to a lamp and the LED elements in the lamp being destroyed by too much current being forced through them
As I recently wrote, I don't understand why some people seem to have got it into their heads that the general term "driver" (and, in context, specifically "LED driver") relates specifically and only to drivers which are constant-current sources.

In the following, note that the search term is in quotes, so that all of the Google hits relate to items which contain the exact phrase "Constant voltage LED driver" ....

1656097108396.png


... this seems to indicate at least 230,000 examples of people who do not think the same way as you.

Kind Regards, John
 
Joined
3 Nov 2006
Messages
26,939
Reaction score
2,901
Location
Bedfordshire
Country
United Kingdom
The use in incorrect terminology is too deeply entrenched in common language. Nothing can change that now

What can be done is to try and explain the differences between an item and its common but incorrect title

Case in point was a wedding venue back in 2017

Their illuminated table decorations were designed to operate from a 12 volt battery, each decoration used LED tape, 24 LED elements in 8 triplets connected in parallel.

LED strip trpilet.jpg


When the room layout was changed and most tables were then close to a wall It was decide to replace batteries with a supply.derived from the mains,

As they were LEDs it was obvious that an LED driver was needed.

12 decorations were converted,

Switching on the first converted decoration produced a short lived very bright flash of light,

The other 11 wre restores to battery operation

Investigation

Supplied with constant 12 volts from the battery the 8 triplets per decorations took a total of 200 mA

A test rig was set up using triplets very similar to those in the decorations, they were destroyed when then LED driver was switched on.

The LED driver wanted to drive 300 mA through the array of elements and raised it's output voltage well above 12 Volts. A peak recording voltmeter recorded 32 volts on the supply to the triplets

Follow up

The owner of the "High Street" lighting shop that recommended and supplied the drivers replaced the LED drivers with DC power supplies. He now fully understands how much damage can be done by use of the wrong terminology
 
Joined
27 Jan 2008
Messages
19,978
Reaction score
1,958
Location
Llanfair Caereinion, Nr Welshpool
Country
United Kingdom
However much we personally think a bulb grows in the ground, a lamp is the whole unit that traditionally sat on a spigot, or a transformer is a wire wound device with no electronics, what matters is what name the manufacturer gives to the device, if the manufacturer calls a switch mode power supply voltage regulated a driver, it does not matter how much we think it is the wrong name, its called a driver.

It is the same in other trades, engineer I consider as some one who has gone to University, but in USA he is what we call an engine driver, who around here has to first train as a fireman, and the fireman lights fires, he does not put them out until ready to go home.

But the question was about light output, not the names given to devices, so a LED Light Strip 1656138508666.png has a number of components. The box Lidi-Smart-strip lamp.jpg shows what it is and this Lidi-Smart-strip lamp3.jpg shows what it looks like, it seems one can select either colour changing or colour temperature changing, the wires are labelled FW, G, B, R, C, VCC and there are three chips repeated D1, D2, D3 the D2 has 6 connections and is the colour changing the D1 and D3 are warm white and cool white and one can select the brightness of each to get the colour temperature required, there are three resistors to stop elements being over driven. The power comes from a wallmart (2) but this feeds the LED controller (5) the total power consumption is 22 watt, but the LED controller stops one using the white light and coloured light together, here shown lighting a display cabinet, also have one lighting kitchen counter.

This strip light is bright, in fact two bright, so never run at full output, however the two Ikea strips in the cabinets either side are not flexible, and no where near as bright. The Ikea ones would be useless under the kitchen cabinets lighting the work top, although they do make the ornaments look good.

The problem is one tends to buy strip lighting from the internet, so until it arrives one is not really sure what you are getting, and common not to have any lumen output advertised. The Lidi lights shown do not show lumen output, comparing with other lights I would guess at around 1800 lumen when full on, which is about the same as 4 x E14 bulbs. But the Ikea strip light would be less than one E14 bulb.

I would expect around 60 lumen per watt for more strip lights, although some can be down to 25 lumen per watt, but in the main they are for decoration not lighting a room.
 
Joined
27 Jan 2008
Messages
19,978
Reaction score
1,958
Location
Llanfair Caereinion, Nr Welshpool
Country
United Kingdom
Typical LED driver "Output Voltage: 15 - 24V" "Output Current: 350mA" it does not take much to see you can't use that to replace a 12 volt battery. Advert is here if the buyer can't read the spec then they should not be doing the buying, simple.
 
Joined
3 Nov 2006
Messages
26,939
Reaction score
2,901
Location
Bedfordshire
Country
United Kingdom
Typical LED driver "Output Voltage: 15 -

which is a minimum of 5 LED elements connected in series. What will that driver do if the total forward voltage of the chain of elements is less than 15 volts.
if the buyer can't read the spec then they should not be doing the buying, simple.

if the "High Street" trader cannot understand the spec then they should not be selling the items ( or at least not until they have been educated ),
 
Joined
27 Jan 2008
Messages
19,978
Reaction score
1,958
Location
Llanfair Caereinion, Nr Welshpool
Country
United Kingdom
I would not expect most supermarket assistants to know the products on sale, in the main they put the items on the shelves and the shopper has to read the labels. If I go to Mollie's sweet shop in Welshpool or Shrewsbury and ask for sweets suitable for diabetics they will direct me to an array of shelves with all sugarless sweets, however if I go to the supermarkets it is unlikely the shop assistance could do any more than read the label the same as me.

In the same way if I go to a lighting shop, I would expect the shop assistance to know what there products do, but if I go to a general electrical/plumbing/ and other products outlet like Screwfix, then I would not expect the counter staff to know much about the products, specially as even their books get it wrong, one is more likely to get assistance from a fellow shopper.

OK the likes of Tandy and Maplin were good, they did have knowledgeable staff, however they have both gone, the British public are not willing to pay for knowledgeable shop assistances.

I would say Mollie's sweet shop in Welshpool is about the only high street shop I use on a regular basis, I prefer in the main to use outlets where I can park outside and don't need to walk ½ a mile to get my shopping. There are three local shops, and I will use them, but shops like this 1656145335243.png are rare now, if I want electrical goods I will normally go to a shop without yellow lines in front of it, I have called into this shop, when I went into town by train, as the larger electrical shops are not on the high street, but he simply did not have what I wanted, think I was after a plug in ceiling rose, I had to instead walk into the local industrial estate where there were two electrical outlets, but on the high street not a chance.
 
Joined
30 Dec 2018
Messages
11,600
Reaction score
1,625
Country
United Kingdom
There are three local shops, and I will use them, but shops like this 1656145335243.png are rare now,

Sadly, that is very true. There is a particularly good shop for such things about 12 miles from here, which is either four buses, or a drive and struggle to part. They used to sell absolutely everything electrical or white goods parts. Unfortunately the original, knowledgeable owner either died, or retired, since when - run by a relative or paid staff, it has slowly gone down hill. No point going in now and asking have you a so and so, for a ??? - The best they can do is ask what it might look like, or can you see one yourself. Such a shame, no wonder people shop on line.
 
Joined
11 Jan 2010
Messages
7,964
Reaction score
660
Location
London
Country
United Kingdom
what matters is what name the manufacturer gives to the device, if the manufacturer calls a switch mode power supply voltage regulated a driver, it does not matter how much we think it is the wrong name, its called a driver.
I disagree. The manufacturer should know what he is selling. If he doesn’t he should be educated.
 
Joined
27 Jan 2008
Messages
19,978
Reaction score
1,958
Location
Llanfair Caereinion, Nr Welshpool
Country
United Kingdom
I disagree. The manufacturer should know what he is selling. If he doesn’t he should be educated.
That may be true in an ideal world, but we don't live in an ideal world, we have huge problems with translations, even the government can't get it right, unfortunately I don't speak Welsh, and reading limited to know a male toilet the word starts with a D, and slow on the road starts with a A, however living in Wales all my life, I know a direct translation may say small house, or blue field, but in real terms it means toilet and green field, maybe the old Welsh were green/blue colour blind.

The same problem exists converting from Chinese to English, or for that matter any other language. So 12 volt in USA is low voltage, but in countries complying with ISO it is extra low voltage, so one can understand why package incorrectly marked.

Even in the same country a phrase can have a different meaning depending on who you are talking to, at work a fireman is some one who shovels fuel into the boiler on the railway engine, but in areas where they don't have steam engines a fireman put out fires.

Screwfix no longer sell the Flomasta thermostat, but when they did it said it was SPST where it was SPDT and it had the option of N/O when temperature raises or N/O when temperature falls, but the person writing the description got it wrong, and this is a massive company like screwfix. They also called it three wire, and it only needed two wires. But the instructions with the thermostat were correct, and screwfix would take it back if turned out wrong type.

And to be fair, what would you call one of these
1656150946371.png
it is not strictly speaking a ballast, as it does not contain a simple choke, but a load of electronics, until we got LED tubes it did not matter, but with LED tubes to convert from fluorescent it needs a different product depending if electronic device or simple wire wound device, it may use switch mode or pulse width modulation technology, but it is not a simple power supply.

So the question is, what name would you give it, other than electronic ballast?
 
Joined
15 Jun 2021
Messages
2,406
Reaction score
589
Location
Wales
Country
United Kingdom
He now fully understands how much damage can be done by use of the wrong terminology
As I said earlier, I suggest that this has little to do with a misunderstanding of the terminology - more a fundamental misunderstanding of the difference between c.c. and c.v.
Even if they had an understanding of the terminology, a mistake of that magnitude suggests they really didn't know what they were doing! ;)
 

DIYnot Local

Staff member

If you need to find a tradesperson to get your job done, please try our local search below, or if you are doing it yourself you can find suppliers local to you.

Select the supplier or trade you require, enter your location to begin your search.


Are you a trade or supplier? You can create your listing free at DIYnot Local

 
Sponsored Links
Top