Diodes are really simple electrical components.
They're designed to only allow electricity to flow in one direction, a bit like a valve.
But, because of the way we make diodes, they're capable of so much more than that. In the mid-1900s some curiously minded
scientists noted that if you push
electricity through a diode (or, more formally if you apply a voltage across a diode) then it emits light, which is why
LEDs are made of diodes. They're light emitting diodes, but
what's really cool is that the reverse is also true. So if you shine light onto a diode
then the diode will push electricity through itself or
more formally, you will measure a voltage across a diode when light is shining onto it, which is why
solar panels are also made of diodes and
one neat consequence of all this is that all solar panels are
LEDs and all LEDs are solar panels
because they're all just diodes. It's a bit like speakers and microphones actually.
They're just the same thing as well and you can use a speaker as a microphone
So in this video you're going to see solar panels acting like LEDs and
LEDs acting like solar panels and then in the next video I'm going to explain how it all works,
so, how a diode works and why that means diodes are used as solar panels and LEDs.
obviously LEDs are engineered to be good the emitting light thing and
actually, they're not great at being solar panels though they can be used in that way and the opposite is true for solar panels
they don't make great LEDs and in fact one of the
shortcomings of a solar cell as an LED is that the light they emit isn't visible.
Can you call it an LED if you can't see it?
This video's a lie.
I know it was my idea. I know there's no one there.
You can't see infrared light with the naked eye but digital cameras can. If you look inside a digital camera
you'll see that there's a filter over the sensor. That's
filtering out infrared light because actually
you don't want your camera to see infrared light,
you want it to see what the human eye sees.
But if you remove that filter your camera can now see infrared light and I've got one of those modified cameras
so here's the camera with infrared light filtered out and here it is with the infrared filter removed and
Here it is with visible light filtered out. So it's just
Infrared that you're seeing and actually look at the lining of my hoodie
Things are really weird in infrared light. By the way, it's near-infrared light, which is the infrared closest to what we can see
It's not really useful for things like thermal imaging
I took the solar panel out of a calculator and look what happens when I apply 14 volts across it.
I also bought some of these little solar panels. Look what happens when I connect it to four 9-volt batteries in series.
What's interesting is if I crack the diodes inside, you can't see the cracks from the outside
but if I pass a current through it and look at it through my modified camera,
you can see those cracks you can actually use that method as a diagnostic tool to look for faults in your solar panels
This is a concentrator photovoltaic, so it's quite niche when you pass electricity through it it produces visible light
Now for completeness here's an LED producing a voltage when light shines on it in other words acting like a solar panel
For an explanation of how diodes work and why all diodes are solar panels and LEDs at the same time
Look out for my next video or even better
Click Subscribe if you super want to make sure that you catch that video also click the notification bell.
I really like the story of the diode because it illustrates how a healthy dose of curiosity in the workplace can lead to world
changing innovations. I like to make sure that my work environment is conducive to
curiosity by having all my previous projects easily to hand so that I could combine them in new and novel ways
but what about your workplace in a 2018 state of curiosity report conducted by Merck just 20% of
participating employees described themselves as curious
Yeah, 80% of participants said that curious colleagues would be more likely to bring an idea to life at work
Check out the 2018 state of curiosity report for yourself and find out what's stopping you from being curious at work
Thanks for Timothy Silverman and for giving me the idea for this video
And for helping me out with some of the concepts and thank you to my patrons and patreon. I'll see you next time