Do LED's Save Money?

'my recent Phillips LED lamp purchases have excellent quality and lumen output'

@ Anon - You put it well - one key factor (as with most things) is buying quality goods - not something from the bargain bin at the local big box store.

GA Anon. Hero. I too believe LEDs will be the dominant lighting for domestic housing in the near future. The operational costs are such a lure that LEDs should not be ignored. The only problem I see right now is that everything residential is for retro-fit rather than using its own system. I think if some industry like Hubbel just moved towards making a complete system for new houses, unique lights, switches, dimmers, wiring etc. Ignore the way a house is typically wired for lighting and use lights that are unique to an LED system. I was trying to install a system with a home I recently (3 years ago) built but backed off when the capital cost looked like it was getting out of hand. With the low wattage we could use much lighter wiring and DC rather than AC. I am not an expert in lighting and maybe someone is aware of a complete residential system using LEDs as opposed to standard systems.

Have a look at small boats and their electrical systems.

The problem with creating your own standard for a new system is if no one accepts it you are out in the cold. Just look at the Beta vs. VHS tape wars or the various standards proposed in the DVD world.

The thing about following a standard is that you get leverage in numbers, which lowers your cost and if you need a replacement bulb or another part, any hardware store and in some cases a super market will carry it.

Even adopting what they use in a boat can be problematic. What if you need something that the hardware store doesn't have? If you live in Colorado, where is the nearest marina?

I agree we don't want to change the basic house wiring schemes. However, I don't think the Beta v VHS is a good comparison. They were both stand alone systems but depended on external outputs to use. What we need is to wire houses that would be better suited to LED or in the near future some of the organic LED and e-paper. We are entering a new threshold of lighting and need to assure that we don't simply install a 19th century technology and then try to adapt it. The dimming of LEDs is a case in point. We need to add drivers (DMX) and then LED dimmer to operate properly. It would be far easier to have a simple programmable driver connected to all the dimmers in one household at the construction phase of the house. My experience with retrofitting is starting to add up in dollars. I see no reason to visualize a unreasonable cost to prepare a house for LED technology nor do I see another technology that will usurp the work done. I fear the opposite will happen if we just keep using the old technology and trying to adapt to it. All in all in my case I will just wait to see where we are going before doing more retrofits. Be assured LED technology will dominate the future lighting markets. My two cents or non-sense.

Good luck. Smart House tried to change the standard, too, and they can tell you how easy that was.

Any way you look at it, you are still pushing for a new standard and that requires buy-in from the majority to get to critical mass so it can succeed.

Does LED has to integrated Numbers in want of required Illuminance level., i.e, number of led to assemble?

In that case does each one of them are having same ageing., i.e, operational life ?

It is not possible to have each with same life , than out of deteriorated /damaged make change in Illuminance output for uniformity?

You must know that any thing made has tolerances & that settings are an average as is life of product.

GET TECHNICAL AWARENESS ABOUT PRODUCT

<...on the exteriors of newer aircraft are in fact LED now and Bo[e]ing is going with LED on the interiors as well...>

That has a lot to do with lumens-per-unit-flying-weight. So LEDs save fuel.

I am going same route as you runing lights off a soler panel for each room and same on my sailboat all running lights are now led and that def works better and brite much less power drop and can leave lights on all night I left then on a week and they was still bright win I got back so they save me cash time and lots more

you can get led's that plug in to a 110 outlet I use two of thouse 3.5 watt bulb's in my hall I have more light then all the lights I had tryed there the two 7 watt useg fluorescent bulbs did not shine far down the hall and only work right under them and gave me a headack so led's work for me

You are comparing apples to oranges here. If your CFL is indeed consuming 250mA @ 115VAC, then it is consuming 115*0.250 = 28.8 Watts. Now that is a big improvement over the incandescent lamp at 65 Watts. In my experience, the CFLs also get quite warm, and I've had several fail due to overheating. I also find the CFLs quite fragile - Ive broken several over the years (but have not reported that to the EPA).

LEDs do of course produce heat, and require heatsinks if they are very compact and higher power, but if that heat is distributed over a volume similar to that of the complete CFL, I believe you will find that a good LED producing the same light will actually run cooler.

As to the light output, LEDs do tend to direct their light in one principal direction, so other directions will likely have dimmer light. Of course you appear to be comparing a 20W LED to a 29W CFL, so of course it will be dimmer... There are lots of new LED technologies appearing on the market: give them a year or two, and I think all doubt over their superiority will disappear...

You don't still use an incandescent torch, do you?. The benefit of leds is lower power consumption & longer life & whiter light- yes go to 12v system. CFL,s- ever taken one apart to see the electronics?-now THAT is power waste!. Leds are here to stay, & new developements such as organic leds will up the bar even further!. Now take lcd tv,s- they had an inverter sytem driving 1400v ccfl- these failed regularly & cost lots to r/p- now we have led backlights- a clearer sharper pic PLUS reliability & far lower power use!(or if you like- wastage!). Cheers.

If your going to run a 12Vdc circuit, by the looks of it (20W LED lamp drawing 1800mA 1.8A) your not going to be able to utilise your existing lighting circuit. 60W incandescent lamp at 110Vac = 600mA 0.6A, effectively your tripling your current load. The average (say downstairs) circuit would normally run I would say about 14 incandescent lamps. So 14 x 1.8A = 25A total load. Whoo your talking about some hefty cable there, at least 4mm/12AWG once you've taken into account all the derating factors. Now running a new circuit with larger cable, I'm thinking in any part of the developed world this is going cost alot of money. Also do light fittings accept this size of cable? Does a 20W LED lamp even produce the same lux level as a 60W incandescent lamp?

you are correct in some of your simple calculations which I had not considered. My viewpoint is reduced power use & longer life- which leds supply. Now- as to your assumption that led lights MUST supply watts equiv to cfl or incand-why?- I can see well enough with a few leds. The reason leds use so much power is that dum bunnies use a driver circuit which WASTES so much power you would not believe- unless like me you measure such- the most efficient way to light a led is to supply 3.6v at the rated current of the led- a simple resistor then wastes very little power - doesn't even get warm- & NO- this is not guess work- I have experimented extensively for 10 years. The reason I said use 12v is a generalisation which would involve using a solar panel, 12v deep cycle batt,etc etc- in other words back to nature!- & yes- a led backlight lcd tv running off 12v dc!.

Actually the most efficient way of driving an LED is to switch it on and off at around 70 hz or so and overdrive it slightly.

Hi Rorschy- I think one of us has got efficiency confused with power usage- my def is the lower the m/a drawn in the circuit(torch eg)- the longer the bat or cell in case of 3v7 Li-ion lasts- I agree switcher circuits allow led to be driven at high ave levels- BUT every one of every driver circuit I have ever seen or built uses on ave 2x power of non driver circuit as I have said. One commercial torch I bought (3w) $40 uses 2x c cells- sure great light BUT power drawn is 1.9A!- dem c cells don't last long!. (Alk). Before using rechargeables have to check current draw & modify circuir if neces so led/s don't get more than their standard rated current as used by maker with alk batts. Cheers.

For a light source, efficiency must be measured in some units of light output, such as Lumens, per Watt of power input. For a given supply voltage, power is directly proportional to current, so as long as two lights use the same voltage, Lumens per Amp would be a fair comparison.

Are you measuring the current at the battery or at the LED? And, if at the LED, are you measuring it with a meter that indicates duty cycle?

Theoretically, a switching circuit should have a higher efficiency than a limiting resistor, since the switch is nearly always either fully ON or fully OFF, so I²R losses are minimized. This theory has certainly proven to be true in practice as far as constant voltage power supplies is concerned. I don't have any experience measuring actual LED flashlight (torch) values, and in fact have no idea which technology is used in any of the several LED flashlights I have.

All of those that I have use smaller batteries than size C, and for the occasional use they get, the batteries last 2-3 years. In fact I have one with 2-3V CR123 batteries that is several years old and still has the original batteries. These are all milliWatt (unknown values, but way under a Watt) flashlights, so it may not be fair to compare them with a 3W flashlight.

Now a 3W Flashlight should draw 1.0A from a 3.0V battery pack. If the power is measured after the limiting device, it still should be no more than 1.1A. I can only conclude one of three possibilities: 1. Your torch is defective. 2. Your measurement of current is defective. 3. the 3W rating is defective.

Hi DKW- my measure of the light from a torch are my eyes comparing the throw of different torches(this is actually one of the best ways)- the current drawn is by putting accurate dmm between batt/cell conn & load- all circuits using inverter/driver can be identified by less than 3v6 bat/cell-eg 1 cell or 2 cells @1.5v- hold the running torch to an am radio-the running circuit is heard over the radio- I believe in experimentation to prove things-NOT theory!(which also has it's place). Finally- by putting simple res in afforementioned 3W torch(disconn inverter)- as much light throw but current red to 0.9A!. So batt is going to last twice as long!- with acceptable light level & throw for 90% of batt life!. Regards-nkwyrer.

Depends on the number of LED's you're driving. the more LED's the more efficient it becomes. because if you multiplex them only one LED is lit at any given instant. And since they are pulsed, you can get away with driving them to their limits instead of "average" values because they have time to cool back down between pulses. Every LED alarm clock uses multiplexed displays as an example.

I think it is overly broad to say that every LED alarm clock uses multiplexed displays.

I have at least one that uses 4511 seven-segment drivers. I'm virtually certain that they are not multiplexed; They simply turn on those segments defined by the BCD input. That one is 35 years old (and still working just fine).

I have another that is only about 30 years old (also still working just fine), that I have not opened to look at the circuitry, so I don't know which chips it uses. However, when I swing it rapidly past my vision, I see multiple distinct images, so it is pulsed with a very low duty cycle, but those images are all complete digits, so the segments are not multiplexed. When I swing it vertically, all the digits appear in horizontal rows, so the digits are not multiplexed, either.

I just got out my 1970's TI calculator, and put batteries in it to check (it too still works perfectly): it also is pulsed with a very low duty cycle, but again, every digit is a complete digit, so the segments are not multiplexed. The rows of characters slant opposite directions for alternate passes past my vision, so the characters are multiplexed.

I suspect that newer LED clocks probably do use a microprocessor to turn on individual segments one at a time, but all my newer digital clocks are LCD, so I can't check...

On the other hand, the multiplexing issue is a moot point for this discussion, since most, if not all, of these displays use a low duty cycle pulsed display. The off (cooling) time appears to be at least 50 times longer than the on (heating time). With resistor current limiting, there is no cooling time.

Another significant point has to do with human perception. Unless I am mistaken, human perception of brightness of a light source is more closely related to peak brightness than to average brightness, for pulse rates above 50Hz or so. If this is true, then a source producing very short pulses of very bright light should appear to the human eye as brighter than a source that continuously produces the same average light output. I just checked four different LED flashlights(torches), and none of them appear to make use of this principle; they all produce continuous unmodulated streaks of light when passed rapidly across the field of vision. This is true even for one which is dimmable (whether dimmed or not), which really surprised me. So either I'm mistaken, they pulse at a very high rate (which I seriously doubt), or none of these is as sophisticated as they could be.

I'm anxious to learn more...

I've been using both CFLs and LEDs through out my house, indoors and outdoors for over ten years. I have several CFLs that I use outdoors as spot lights and for decorative lanterns. Temperature ranges in PA are from 110 F to -20 F. Two weeks ago my first out door CFL burned out it was used in a dusk to dawn lantern for close to 11 years. I use CFLs in my garage door openers they have been in there for over 6 years no damage from the vibration, heat (temps can get up to 140 F), or cold. Every one of the LED lights I used outside have burned out average life 1 years plus they cost twice as much as the CFL. The only area I use LEDs, that is very reluctantly, is where I have dimmer lights (4 lights in our dinning room).

I did switch our x-mas lights to them but that's getting expensive because they usually only last about a season or two.

LED have a long way to go before the can prove themselves to me. I'll stick to the cost effective CFLs.

Average savings right now since I switch to CFLs (w/ six LEDs) is about $150 a month.

To save $150 a month you need to save 5 KW ten hours a day for 30 days at $0.10 per hour. I didn't take into account the AC but it should remove about 10-20% from the net light load in this consumption.

To save 5 KW in lighting, you need to use a lot of lights! Do you own a hotel?

Nope don't own a motel, through it feels like it some times there is someone there 24/7.

I compared my electric bills looked at costs, KW/hr, temperatures, etc. Pretty simple math really. I figured out two similar years with temperatures one before we changed the bulbs to CFL and one after we changes got the difference and divided it by 12. Came up with an average of around $150 a month.

LED will always be cheaper than conventional candecent light. Candecent light is heating tungsten wire to glow under vacuum by passing amperage through wire. Glow is light

LED on the other hand convert amperage to light. Older LED version was producing heat and had poor chip quality and poor thermal management. If you buy CREE LED chip and CREE heat engine what you will observe is your efficiency went from 5 percent to 95%.

95 % of conventional bulb consumes power to generate heat and effectively we use 5 % total for lighting area. In LED we use 95% for light Technology is still evolving and presently at the stage which needs carefully selection light engine and LED chip. CREE is world leader in this technology and with single system with LEDS you can light up entire football field and is still touch able they are not in vacuum so you can have different color case to have different light and benefit is more than our imagination can run

I think you mean efficacy rather than cheaper - more lumens per watt consumed.

LED's convert 95% of the watts to light? You are being wildly optimistic! Maybe 3 or 4 times better than incandescent is closer.

You are correct it is efficiency. As far as conversion goes as the hot spots under LED is eliminated efficiency will be better than induction lighting and all the calculation say is it will around 95%.

Anything will be better than current incandecent light bulb. Even induction is about 80% better than current bulb technology and lasts more than 100,000 hrs

I have never seen anyone claiming an efficacy of 95% yet.

Induction lamps - I was interested until I started looking up prices - from what I saw they are quite costly. The long life would never pay back the initial cost.

From a cost of ownership calculation, incandescents still have all of the other technologies beat by a mile. it is the initial purchase price that blows them all out of the water. the energy savings for CFL's still can't beat the purchase price savings when you look at their realistic lifespan vs the published lifespan. I've also seen CFL's catch fire when the ballasts fai, so you also have to factor in the increased risks of fire. Incandescents don't catch fire when they fail.

It cost me $12.97 for a 12 pack of GE CFL bulbs with a guarantee life span for 5 years so far they have last up-to 10 years equivalent to a 60 watt incandescent bulb. Long life incandescent 60 watt bulb from GE 4 pack $7.99.

As far as causing fires there has been only one report fire dealing with CFLs, caused by a malfunctioning socket. I have seen incandescents catch on fire, my neighbor throw a cloth over it and it ended up burning his house down.

That guarantee of 5 years is BS. first off, the manufacturers know that nobody is ever going to keep their receipts for a light bulb for that long, so the odds anyone will cash them in are minuscule, and that 5 year lifespan is theoretical at best. real life lifespans in most sockets and under real world usage conditions is usually far less than that.

And I'm not talking about putting something flammable in contact with the bulb, any bulb will do that, yes, even CFL's and LED's. I'm talking about the ballast catching fire when it shorts out internally.

And if you are paying $8 for a pack of four incandescent bulbs, you are crazy. You can get a six pack from GE here for under $3.50, vs $15.47 for a 12 pack of no-name generic CFL's from China.

I'm sorry but you assumption is incorrect. I have brought one CFL back and several LED and gotten my money returned to me. It must be a state thing because most people from PA save their receipts. Avg lifespan of CFLs in my house so far is around 7 years I just retired a 11 year old one that was out doors. It wasn't because it burned out I had to put a new lantern up and it didn't fit in any more. So I guess that blows that theory out of the water.

According to the articles I've read the only recorded incident was in Chicago and they believe it was the fixture not the bulb. Where is your proof? CFLs LED don't get that hot maybe your confused with halogens now they get hot.

$8.00 is the going rate for long life incandescents from GE 100. If you go to Sam's club CFLs from GE a pack of 8 goes for $12.98. I didn't realize that GE bulbs made here in the USA are really cheap ones made in China.

My proof was watching the smoke coming out of the fixture in my living room.

I've lived in my house since 2000, and by your standards, I should not have had to replace most of the CFL's in the house. There is not a single CFL that has not been replaced at least three times in this house. There ARE incandescents that are rarely used that have been here since I bought the house.

The average lifespan of the CFL's I've had averages around 18-24 months, some have gone longer, some less. NONE have gone 5 years.

Sound like bad wiring, or just bad luck. I never heard anyone one having that much problems, I'd be scared to run anything in your place.

And NONE of the CFL's are made in the US, they are ALL made in China, yes even the GE branded ones, same with Phillips/Sylvania, and all the other brands out there.

And by the way, you can get generic incandescent bulbs for a fraction (1/2 or less) of what GE charges, so the cost savings is magnified.

I was comparing apples to apples (GE products to GE Products) not apples to oranges (generic to generic). That how your supposed to do research, remember back to your school days.

GE CFLs and LED are made in CA since 2007. Last time I check CA was still part of the USA. I almost forgot GE has several big plants in Cleveland Ohio where they make CFLs and LEDs.

Not anymore they aren't.

http://blog.aflcio.org/2007/05/12/ge-workers-say-screw-that-made-in-china-bulb/

And i was comparing GE branded 60W incandescents to generic 14W (60W equivalent) CFL's in 12 packs because that was what i could find. If you compared apples and apples (assuming I could find them.) you'd probably find the ratio even worse.

The still have plants in CA and OH that make CFLs and LEDs, research on my friend.

Are they the GE 100 that I was comparing to their long life bulbs.

The bulbs I get are GE; they are 18 watt; they all have lasted over their 5 year mark; I can purchase any time I want in packs of 8 for $12.00 (about $1.50 a bulb); and the kicker they all say made in the USA.

I guess in your area you only have access to junk and poorly constructed products at higher prices.

Um, no they don't.

http://www.pittsburghlive.com/x/dailycourier/s_699116.html

http://www.alibaba.com/countrysearch/US/cfl.html

If you want to see the list of US CFL and LED Manufactures.

In the U.K we have been plagued with counterfeit product of everything you can imagine possible and i mean everything, some of the worst i have witnessed is circuit breakers with nothing inside then other than a wire between terminals and a weight to make it feel good and cables with copper plate over cheap metal and insulation that burns like wax.

we really must use products from known quality suppliers to have any chance against these types of product, they look very authentic some of them. No more boot fair bargains unless you can guarantee they are genuine, and i don't mean the standards that are printed on them or the box it's in.

I had one particular corridor in a place That had 26 twin 18w CFL fittings and as you say the ballast (when bulbs fail particularly) would dramatically fail, fortunately they where installed in fire proof enclosures, however not every body installs them in such a way. I changed every one of those ballast over time, and we had noticed that the new circuits they sent us where modified versions, and yes some of those failed too.

I did want to do some power quality analysis but my boss thought i was being over zealous, (didn't have a clue what i meant) as the place was rammed with all kinds of power quality issue spewing equipment.

A lot of fire with CFL and other types of bulbs that get hot are generally how they are used, part of the design process is to eliminate such problems, for instance using the correct type of tube (sleeved) or cover in a stable full of hay.

Wouldn't it be nice if the consumer had a choice of what to buy based on their own, perhaps unique situation and their personal preferences instead of the gubmint telling you what you can't buy?

But there seems to be a disturbing trend that the ruling political class doesn't think the public at large is capable of making informed decisions for themselves.

Back to the point that I was trying to show.Isn't 1amp the same in all light bulbs?Im talking about the use of power /current, to light that bulb.If the led takes 1.8amp's [at15vdc] and a different bulb takes .85amp's [ at115ac ] which one uses more power?I know that in certain places they do save money/power.

tks John.

Power is power is power, regardless of what is using it. P=VxA.

Well, if you really want to do this right, you need an ammeter, voltmeter, and a device to measure lumens and the light spectrum for which it emits light.

The problem is that some of the manufacture claims are not exactly accurate, particularly for those foreign made goods.

Once you do that analysis you will have a better idea of the true efficiency of the two types of lamps on a lumen per lumen basis.

Even at that , the spectrums may not match, which affects how we perceive luminosity.

They do have a choice. No type of lamp is being banned in the US.

Not true, 100W incandescents will be unavailable starting next year, 60W, will be next.

The last incandescent mfg plant in the US closed last month.

100 W in 2012

60 W 2013

40 W in 2014

Get out your umbrella the sky is falling!

Higher efficiency requirement - yes - banned they are not.

Quote from Energy Star:

The Energy Independence and Security Act of 2007 (the "Energy Bill"), signed by President Bush on December 18, 2007 requires all light bulbs use 30% less energy than today's incandescent bulbs by 2012 to 2014. The phase-out will start with 100-watt bulbs sold starting in January 2012 and end with 40-watt bulbs sold starting in January 2014. By 2020, a Tier 2 would become effective which requires all bulbs to be at least 70% more efficient (effectively equal to today's CFLs).

It's not entirely correct to say "CFLs will be required" or "incandescents will be phased out" because the standards set by the bill are technology neutral, and by 2012, a next generation of incandescent bulbs could satisfy the 30% increased efficiency. There are also other lighting technologies, such as halogen and LEDs that will be able to meet the new requirements and are expected to both increase in performance and drop in cost over the next few years.

As they say - it should be new efficiencies to be phased in as no type of lamp is being phased out.

Another tidbit - again from Energy Star about extemptions:

There are many types of incandescent bulbs that are exempt from this law:
--any kind of specialty light (ie. bulb in refrigerator)
--reflector bulbs
--3-way bulbs
--candelabras
--globes
--shatter resistant
--vibration service
--rough service
--colored bulbs (i.e. "party bulbs")
--bug lights
--plant lights

Quite a thread! Almost all of the green myths and the old guard myths are represented - in full blown glory and BS.

How right you are!!!

It gave me a good laugh though.....

Maybe so, but . . .

I'm not so naive as to believe that the architects of this legislation didn't intend to ban incandescents. They knew exactly the outcome even if it wasn't an outright ban. Never underestimate the cunning of a politician.

Incandescent bulbs will disappear from the marketplace except for those specialty applications. You effectively won't have that purchase choice.

You want to see an example?

Try to buy a consumer electronic item in the U.S that is assembled with tin-lead solder. Sure, it isn't banned in this country, but other forms of regulation effectively have removed it from the marketplace. Ever wonder why cell phones die in a couple of years? The pitch of the parts is getting so small, and power levels are so low, you can't ignore tin whiskers (or burn them off).

Chuckle and laugh, call it old guard myths if you want, your choice to purchase a 100W incandescent bulb that you want to put into your attic, basement, outside in the dead of a Minnesota winter is going away in 2012.

Your liberties are being stripped away a little at time. In fact, you may even be in favor of some of these "good ideas". Statists know how to play these games. Be careful of what you wish for, you might get it.

yeah, that and "if you like your Health plan you'll be able to keep it"...

Tell that to my Insurance Company....

And it isn't just the insurance company. YOUR employer may very well find it more economically favorable to simply discontinue funding the health insurance and pay the annual "fine" for not providing health coverage and let you get it from the gubmint.

Many larger companies are "self-insured" for health care benefits and simply pay a health care insurance carrier a flat rate to administer the plan (and get the negotiated rates) rather than pay premiums directly to the carrier. This can be a huge cost savings especially if the company encourages healthy behaviors (wellness programs, gym memberships, mini-clinics for BP, cholesterol, cancer screenings, etc.) and has a generally healthy population.

I don't believe the structure of our health care bill was a coincidence that encourages this kind of transition. The camel's nose is under the tent. It will be very difficult to push him back out. Call me paranoid but I am old enough to have seen where hidden agendas take us under the guise of "beneficial" legislation. They won't outlaw private health insurance, they will make it unattractive, and it will disappear on its own.

"The camel's nose is under the tent. It will be very difficult to push him back out."

And for good reason!

Have you ever smelled a camel's breath?

Dam / from led's to the [some call it obama ] health care plan.

I just wanted to know for sure that 1 amp at 12vdc was the same as 1 amp at 115vac.That would mean the same power/ I think.Thats all.It looks like a 100 watt inc.at 110vac uses about 1 amp. and it looks like a 20watt led at IV 18vdc you come out with 1.1 amps. so now it takes five leds to make the 100watt light bulb. That would be using 5.5 amps.for the led.SOOOOOO led using 5.5amp to 100watt inc. at 1 amp. Hummmm now that is about a 5 to 1 ratio.

oh well I tried. lol

Johnny

No. Power (in Watts) = Amps * Volts

Obviously, if you increase the voltage with a constant current you must also see a corresponding increase in power.

No its not the same.

1 amp at 12vdc = 12 watts

1 amp at 115vac = 115 Watts.

OK?

Come on Anon & Andy - you are quashing hundreds of green schemes by insisting on science and engineering!

Simply wishing makes so much more possible!

Andy, thank you.thats better.

Johnny

Funnily enough all MIL SPEC equipment is still made using lead based solder because they know tin solder alone is crap, and it is crap.

Wish the old days of incandescent lamps and simple life to come back.

The more technology the more miserable man's life.