For some reason, I’m always interested in why things are called what they are. For example, I’ve been compelled in the past to research what Absorbine Senior is. Not that it is important, but Absorbine Junior is a smaller size of horse liniment, so you don’t have to buy a drum of ordinary Absorbine just to rub down your sore thumb. So it isn’t a mystery that I would find myself musing over why we call a flashlight a flashlight.
You don’t think of a flashlight as flashing, under normal circumstances, at least. Turns out the answer lies in the history of the device, its poor beginnings, and our willingness to treat imperfect components as though they were much better than they are. That last point, by the way, still has ramifications today, so even if you aren’t a fan of flashlight history, keep reading.
Portable Lighting
Ever since people learned to use fire, there’s been a desire for portable lighting. Torches, candles, and even oil lamps have all had their place. But burning things for light in small cramped spaces leaves a lot to be desired. It isn’t surprising that people quickly turned to electricity when that seemed to be feasible.
To make a good portable light, though, you needed a good battery and a good bulb. Both of those things were not immediately forthcoming. Early batteries, in particular, had wet chemistry. They were heavy and they needed to be kept upright.
The patent assignee — the American Electrical Novelty and Manufacturing Company — donated a few of the devices to the New York City police department. They were impressed, but the bar was pretty low and we wouldn’t think much of these lights today. The company did make a success of it, though, and would eventually become known as EverReady.
You’ll notice that even in the early advertisements, the word “flashlight” appears. It turns out, the low-quality battery and filament conspired to create a light that wouldn’t stay on very long. Turning the light on almost immediately caused the battery voltage to droop. The result is you’d get a little flash of light that would immediately dim until you let the battery rest for a second.
Better Everything
Of course, everything gets better over time when it comes to electronics. Tungsten filaments were a big help and battery tech got better, too. These days even an incandescent bulb isn’t found very often as solid-state equivalents are generally better. If you do find a regular bulb, it is probably filled with gas like xenon.
Still, a clean, cool portable light had its uses. By the early part of the 1900s, you could find 101 Uses for a Flashlight and a wide variety of different types were available, as you can see in this pamphlet.
Circuits
Even today, lightbulbs are a strange circuit component and require special handling. We like to think of them as purely resistive loads with stable characteristics and we like to think of batteries as ideal voltage sources, too. Neither of those things are, of course, true.
There are really two things, at least, that happens when you try to power an incandescent bulb. First, a real battery isn’t perfect. So while you may think that the battery looks like a perfect 1.5 V cell, it really looks more like a perfect cell in series with a small resistor. The better the battery, the smaller the resistor and the less effect it has on the circuit performance.
For example, suppose the cell has a 1/4 ohm of internal resistance. Further, imagine that you have some (for now) ideal light bulb that will draw 1.5 mA at 1.5 V meaning it should look like a 1000 ohm resistor.
If you look at a circuit like that in a simulator, you’ll see there’s not much difference since the 1/4 ohm is so small compared to the 1K. But if you play with the numbers, you’ll see as the ratio gets smaller, the effect of the voltage and current into the load makes a difference.
More Problems
The other problem with a practical flashlight is that filaments don’t act much like resistors. A filament will have a certain resistance value when cold, but that resistance will increase rapidly when heated. This change in resistance causes an inrush current when you apply power that can be many times higher than the nominal operating current.
This can be a common problem when you are trying to drive a real light bulb directly from a digital output. That initial inrush current can cause havoc with an output that is rated sufficient for nominal operations. In some designs, the varying resistance of a lightbulb is used as a design parameter.
So all these things combine to give us the flashlight. A high-resistance battery that droops as the poor-quality filament draws a high inrush current. It was fortunate, I suppose, that any light was forthcoming, at all.
Nowadays, of course, a flashlight doesn’t flash unless you want it to. There are gas-filled bulbs, LEDs, lasers — even our phones have a dedicated flashlight key. Some flashlights have a lot of LEDs. Or, you can go with fewer LEDs but more — ahem — power.
>A filament will have a certain resistance value when cold, but that resistance will increase rapidly when heated. This change in resistance causes an inrush current
Nope. The much lower cold resistance causes an inrush current not the *change of resistance*.
As soon as the filament warms up, it draws a nominal current.
Both of you jus said the same thing, but from two different angles.
The change of resistance (large increase after warm up) is at the tail of the inrush. It is not the *cause* as stated.
if there was no change you wouldn’t say there is an inrush, would you?
Yes you would.
If you really want to get technical about it, there is no inrush of current with a resistance load. Current starts flowing and then as heat causes the load resistance to go up, the current goes down. If there were no resistance change due to heat buildup then the current would be constant. In other words, there’s a reduction of current and not an inrush of current.
Current inrush is usually associated with reactive loads and there can be quite a difference between inrush current and constant load current. Think startup current for a motor, which can easily be 5X higher than it’s run current.
The cold resistance is the cause of the inrush (by definition: a large amount of current at the moment of switching) and the warming up and *subsequence* increase of resistance *drops* the current back to nominal.
Al is mixing up the cause and effect. i.e. causality Resistance goes up won’t cause an inrush.
By your definition there is no such thing as inrush current, but however it’s created it exists as a concept and we’ve named it.
Edison didn’t complain about others moving into his turf?
I’ve read that he sold lighting initially. The idea that the electricity coming into a home could be general purpose came later
Edison made and sold concrete, his turf is the sidewalk. His company logo is embedded in the concrete sidewalks at his museum. Top quality concrete was his specialty, it still looks good 100 years later.
well, he did have a lot of help in the fact that gas was sooty and impure, and in “early-adopter” environments like theaters, the fumes could get bad enough to cause audience members to experience bad headaches and even pass out, not to mention accidental fires. “Natural” gas is, in fact, mostly methane, a fairly dirty methane at that. In the rush to modernize to gas, cities practically set themselves up get the next “upgrade” to electricity. Edison made the mistake of championing (more specifically, getting patents on) DC current, which in practical terms meant selling a generator along with lights!, because DC current couldn’t carry far. It wasn’t the “idea” of electricity in the home, it was the problem that General Electric could send electricity far from a centralized generator (with credit to Tesla), and Edison couldn’t. Under Edison’s model, practically every house would have to have it’s own DC generator. Which may have been empowering to wealthy early adopters, but not good if you want to create a grid with centralized electric power companies. That’s a vast oversimplification, but I hope it clarifies some of what you touched on.
Mostly I wanted to mention “torch”, the term used not only throughout Great Britain, but nearly all the former British colonies, makes a heck of a lot more sense than “flashlight”. ;)
“General Electric could send electricity far from a centralized generator (with credit to Tesla)”
Some mixup here. Westinghouse Electric was the AC-company. GE was Edison’s company.
“General Electric could send electricity far from a centralized generator (with credit to Tesla)”
Some mixup here. Westinghouse Electric was the AC-company. GE was Edison’s company.
No that’s a myth that Ge still likes to propagate. Ge was basically a creation of the financier of JP Morgan who put together a number of assets to create GE including Edison electric. This was because Edison’s DC system was being beaten by the Westinghouse AC system, and he wanted to consolidate his assets. Edison was given a board seat, but actually had little involvement with the company
Edison was also helped by the fact that he was in the right place to create a new market for coal. And the people who made money off coal were eager to help him out.
Everybody hears the tales of his efforts to wire up New York City, but few note that he also did much of his R&D in the small cities of the central Pennsylvania coal region.
A lot of his early backing came from mining barons who were eager to expand their markets, and understood that while heating furnaces might run for 4 months of winter, the boilers that would generate this newfangled electricity thing would be burning 24 hours a day, every day of the year.
Natural gas came later. Firts there was coal gas mixed with water gas for a balance between lighting and cooking.
And “torch” as a name for this device makes even more sense when you recall that the *full* name is “electric torch”. :-)
Not to mention his turf was sown with other people’s ideas.
In England we don’t call these devices “flashlights” we call them “torches” just like we were still setting fire to some paraffin on the end of a stick.
“torch wood” is an anagram of “Doctor Who”
…I never realised that… :-O
TILS
Tnx!
+ Astrid – Tardis.
“Who” taught spelling where ?
Which seems unusual considering that the article says it was patented by an Englishman, called a flashlight when it came out and the English still call them torches, language is crazy.
The generic versus genericised terms that get adopted are quite interesting: “saran wrap” is a genericised term in the US whereas we use the generic “cling film”, I think “Hoover” is a genericised term on both sides of the Atlantic, and then there’s “Scotch tape” and “Sellotape” both are genericised terms for the same thing.
In the US we call them vacuums or vacuum cleaners. Seems to be a very British thing to have a Kirby Hoover or a Dyson Hoover. Does the owner of the Hoover brand name ever take out ads in British magazines telling people that only Hoovers are hoovers?
Xerox has done that in the US. Only a Xerox copier is a xerox, the others are just copiers.
Velcro did it most hilariously https://www.youtube.com/watch?v=rRi8LptvFZY
Really? I’ve definitely heard US-ians using the genericised “Hoover”, maybe it’s something that has changed over time? I don’t remember ever seeing any anti-generic Hoover advertising, but maybe I’m just not looking out for it.
Over here we’d only refer to “photocopier” not even “copier”.
I’ve seen that Velcro thing before, personally I think they’ve lost that battle, and I think they lost it right at the beginning by not having a name for the product. “Hook and loop” is not descriptive enough, they should have called it “Tssssssch” or “Rip Fasten” or something like that.
We also hold them like you are shaking hands with it but the USAians seem to hold them like they are going to club someone with it.
We USA folks hold them like a handshake. My understanding is holding like a club allows police to use as a club if needed. It also allows the holder to also punch while holding the flashlight. Television usually shows police/military holding that way.
Well, _we_ don’t cal them flashlights.
We call them “torches”.
Which is admittedly even less accurate.
>> We call them “torches”. Which is admittedly even less accurate.
Unless they have a damaged lithium battery, at which point it’s more accurate than ever in the history of pocket torches.
Because a torch is a stick with flame on the end? But then why to people always feel the need to add
“Flaming” to the term?
Because you can extinguish or not light up a torch in the first place, and it would still be a torch.
I think because there are other torches that don’t burn, they glow
101 uses = stuff you can’t do in the dark, a list as long as you want it to be. Closing windows during a storm should be #101 cuz what?
I thought the name would relate to the type of power switch you’d often see on older flashlights. Beside the on/off slide switch was a push-button to provide a momentary flash of light, presumably for sending messages.
I like “torches” much better than flashlight.
However, every flashlight I ever had “flashed” more often than it provided steady light. That is, when it worked at all. That improved somewhat when maglights came along. Now with decent LED lights, my flashlight no longer flashes — unless I mistakenly activate one of those accursed strobe modes.
It saves time too.
In the UK if we have a flashlight we whack it on the side, that usually turns it into a torch.
[Obligatory hackaday hack]
aka Percussive Maintenance
Growing up poor in the 1960s, a flashlight was something I wanted, but could not “afford”.
If I had one, the cheap alkaline batteries didn’t last long, and a short drop would break the filament loose inside the bulb and maybe shatter the lens.
So, to compensate, if you will, I now “every day carry” a sturdy LED flashlight with a rechargeable battery.
Also, I probably didn’t have a “magnet of my own” until High School…
I didn’t have much use for cranky old flashlights back in the day – but the carbon/zinc batteries in them could make nifty arc lamps running on toy train transformers with very primitive pie pan rectifiers.
What is a “pie pan rectifier”?
As a kid I made a rectifier using a disposable aluminum pie pan, lots of lead solder, liquid electrolyte, and something to keep the anode and cathode from touching. I pulled power direct off the mains and struck some serious arcs on my carbon rods. My father would have been horrified. Anyway, here’s another way: https://chestofbooks.com/crafts/popular-mechanics/The-Boy-Mechanic-700-Things-for-Boys-to-Do/How-To-Make-An-Electrolytic-Rectifier.html
The resistance characteristics of flashlight bulbs and more especially higher-voltage indicator lamps can be useful. For example, years ago we had a problem with a paging system that used a telephone input: when the telephone input went “hot” at 48v open circuit, there was a loud pop in the paging speakers. We put a 48v lamp across the line and its low cold resistance damped the “Pop”, and once it warmed up (in about 250mS) its resistance was high enough that the audio signal came thru with little attenuation and no distortion.
29. Handling Soil Explosives. Everyday activity in 1917?
probably refers to explosive powders such as gunpowder, coal dust, or grain dust. all of which tend to go boom when exposed to fire or a spark and would be rather mundane items back then.there are probably other substances that fit that description not named those 3 are just off the top of my head where explosive powders available in 1917 homes and business are concerned.
Flour go boom.
It’s usually used by farmers. So, yes, it was an everyday activity because farming was a thing WAY more people did a hundred years ago. :-)
Stump/stone removal from fields.
A dry mix of sugar and sodium chlorate, which is a weed killer. My paternal grandfather used it for blowing up stumps and stones. For a house addition he was working on, a buried lava flow was in the way of part of the foundation. So that rather energetic mix was applied, and blew some large pieces of lava rock over the 2 story house, narrowly missing a car parked on the other side.
I have removed the incandescent bulbs from my flashlights, and exchanged them for LED drop in replacements. I get FAR better battery life from this setup. Also: the flashlights in my cars are LED and use CR123 Lithium batteries, which decreases the odds that the battery will be dead when I need light. No more trying to change a tire by dim, flickering yellow light!
Flashlights are wonderful tools, but until LEDs and lithium batteries, they were unreliable.
You could look at the old flashlight as an optimum design. The resistance of the battery served to limit the inrush current caused by the cold filament. Much like a slow start circuit. As the resistance of the filament drops as it heated up, the small resistance of the battery didn’t matter as much. Had they only had low resistance batteries that provided much larger inrush current, there would have been much shorter bulb life and much more inrush current flowing through the switch and wiring during start up. Overall I think it worked out really well for them.
Huh.
Absorbine is owned by the extended family of a childhood friend of mine. Weird.