Hey guys, welcome to ask an electrical engineer part two.
What happened is we got so many questions.
The video was given get crazy long, so we've actually split it up
and we're gonna jump back in to more questions
that non-engineers have for us electrical engineers about LEDs.
Next question, are LED is better than HIDs?
HIDs I believe this question must be directly related to cars, if I'm not mistaken.
So, LEDs are better than HIDs (high-intensity discharges) if I'm not completely off my rocker
and that is where old-school headlamps, they were halogen
and then they switched to HID which is a gas discharge type.
And now the newest most expensive not even that expensive cars have LEDs.
The reality is yeah, they're better.
They are more directional which is a good or a bad thing.
Some people like they don't like the way LEDs look and so that's a more subjective thing but they last longer.
They're gonna be more robust especially in a car that's getting jolted around like that.
There's no gas and no filament to be jounced around or to be broken.
And so yeah, other than the subjective
"Do I like the way it looks?" "Is it blinding me in a way that I don't enjoy?"
LEDs are quantifiably better than HID or HID car lamp "headlight thingamajiggers".
That's my technical take on it.
Are LEDs good for growing "plants"?
Well that just got weird.
So, LEDs are good because you can get them to emit exactly the spectrum you need for a plant to grow.
Now if you're going to just grab some random LED off the shelf
that you use for lighting your house, probably not going to work.
Maybe depends on which LED. But there are LEDs out there specifically for growing plants.
And those make sure they hit the lines of the spectrum
that plants need, so very much on the green I believe, no because that's the part that reflects,
that's the part that doesn't get absorbed, I'm getting everything backward.
So, they do definitely have LEDs that are great for growing plants, use them responsibly.
Moving on, are LEDs directional?
Yes, actually that could be considered a strength and weakness.
LEDs they are very directional.
And I've mentioned this before my wife just loves Christmas lights.
And so our Christmas tree has literally thousands of lights on it.
And I hate the fact that I cannot walk by the Christmas tree without at least 1, if not 3 or 4 LEDs
blinding me directly into my eyeballs.
Because they're pretty inexpensive lights and so they're pretty directional and that's not ideal.
However, other times like when I replaced my fluorescent tubes in my kitchen
by having a string of LEDs instead of a fluorescent tube.
I'm not getting light that's flying right up into the ceiling and reflecting a little bit
but still that's not as efficient as having LEDs that are pointing directly downward.
And you can use a diffuser and stuff like that to make it.
So, it's not as painfully like I can see each LED in there.
So, yes LEDs are and directional.
Are LEDs environmentally friendly?
Yeah, for the most part, they're environmentally friendly.
Now I think this is a matter of comparison.
So compared to the mercury in some gas discharge or in fluorescent lights,
yeah, they're super environmentally friendly.
because mercury is extremely bad for you and the environment
So in that way, yeah they're great.
They're environmentally friendly because they also use way less energy.
They're much more efficient obviously and so those are some big things.
Now, I do want to say that there are certain drawbacks
and I don't want to go too crazy into this and anytime something's made, it takes energy.
So, if you take a huge box of fluorescence and say,
"Hey these are you know five percent less efficient than my LEDs"
and you chuck them in the trash and then you buy a bunch of LEDs.
You just threw a bunch of things away that spent energy to create them
and then these also needed energy to create them.
And even though the LEDs are pretty good I mean they are electronics.
Yes, they're great but like everything we produce nowadays it does have a negative environmental impact.
But I don't think that that should be a reason to not buy them.
I think that just should be a reason to say
"Hey! I've got something that's doing a 95 percent job, let me just wait until it's end of life."
And then by the time that happens, your LEDs are probably even gonna be more efficient,
require less energy to create and cost less
and so you'll be doing everybody a favor.
So yes, LEDs are great, just be reasonable about any upgrades you do.
But if you're definitely doing new construction or a new bulb, yeah I'm all for LEDs .
Moving on, and I feel like I was just on my high horse.
Can LEDs be made from silicon and germanium?
what the heck ... Sure ... sure
Moving on, why do LEDs blink or flicker ?
LEDs do not blink or flicker.
It's the electronics behind them that are driving them that have issues that cause them to blink or flicker.
It almost be like why do cars crash?
Well it's because the people driving them are human beings like me.
And so they're idiots and so they crash into things.
So, that's why cars typically crash.
Except for that's not exactly true because sometimes you know your CV joint comes off
and your tire falls off and go into a ditch and then it's definitely
but you should have been keeping your vehicle up to ... you know, well-maintained.
So yeah, I'll stick with that.
So, LEDs blink or flicker because the power that's coming in needs to be modulated,
needs to be changed in such a way that the LED can use it properly
and that's usually where the issues lie, is you get some cheap electronics in there
or a part that's going bad or some other issues.
And then it's not giving the LED a constant clean voltage and that's causing it to flicker.
Next question, how do LEDs produce white light?
So, that can be done in a couple of different ways.
The first one, the original one was you just had red LEDs, green LEDs, blue LEDs
and you stuck them close enough together.
And you put kind of a phosphor coating on the bulb itself
and voila you had white light.
Now, they've actually been doing some other stuff that I'm not as familiar with.
But they're actually figuring out a way so that the semiconductor material itself
shoots out photons of varying wavelengths to create white light in one led.
And honestly I don't know that much about it.
I know much more about how you just use an RGB to make white
but that isn't as good of a color because even though you have a white light to our eyes,
you stick it through a prism and it comes out a very clear red, green and blue.
And so it's not super great.
It doesn't get the full spectrum, it just hits those three really, really well.
That's how LEDs produce white light. The newer ones, again not so sure.
Next question, how can LEDs be used most effectively in a bear attack?
I have no idea
Are LEDs waterproof?
That's a good question.
LEDs are pretty low voltage, so they don't typically ...
you don't have much problem of like current going through the water
unless it has a huge, a lot of minerals in the water
So, if it doesn't have a just an enormous amount of minerals in the water,
it's not gonna have a low enough a resistance to really cause problems.
More of what you're gonna have issues is again the electronics
that are supporting the LED that are gonna have issues with the water.
So this LED, I could hook it up to a battery and throw it in a swimming pool.
And I would be super surprised if that did not work.
But if I were to take this oscilloscope
and the LEDs that are probably scattered around it for illumination or whatever
and throw that in the swimming pool. Yeah, that wouldn't work anymore
So, the LEDs themselves should be fine.
It's usually everything that's around it that is going to cause problems when you introduce water.