It's easy to forget that a piece of technology—like a computer or a Tamagotchi—is more than just a black box, giving us an answer whenever we need it to. But the minute that we accidentally go swimming with our Tamagotchi and we're forced to watch the eyes on our little alien baby dim before going out completely, it becomes pretty clear that

• we weren't meant to care for other animals.
• something more was going on behind the buttons for feeding and petting Little Shmoop Jr.

There's a ton going on behind the scenes, both with Tamagotchi and electronics that aren't only for teaching us that caring for children is tough. Phones in particular need a way to communicate, and that's done using antennas. For those antennas to work, they're going to need some support from other electronic technologies.

Any time you need a wave, you're going to have to vibrate something. With sound, you need to vibrate particles, and with electromagnetic energy, you'll need to vibrate electrical energy. Most times, you'll make vibrations using a current, which is a flow of electric charge. That current is made from voltage—stored electric energy or electromotive force.

To generate electromagnetic waves, you'll want an electronic oscillator. Like a math function for EM waves, the oscillator takes the input of a direct current (a current that doesn't change directions from an electrical power supply) and outputs an alternating current signal (a waveform current that does change directions). This waveform generation is done using a triode.

Fun fact: triodes were actually invented to make telephones ring. Before that, you had to just pick up your phone periodically and see if anyone was on the other side. (Source)

 

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A modulator can modulate, or change, the periodic properties of the wave like the wave's frequency, phase, and period. Those properties are kind-of important for waves, especially if you're trying to do anything with different waves. If you undo a modulation in order to find the original signal, it's normally called—wait for it—demodulation. To modulate an electromagnetic signal, you'll need to add a magnetic field to a conductor, then create an electric field near the magnetic flux (the flow from the North to South poles). We're going to skip over the technical details on the math there, but you can find more about it here.

Still with us?

Good. Next up is the amplifier. An amplifier is an electronic component that increases the amplitude of a wave. If you talk to an electrical engineer about it, they'll talk about amplifiers as increasing the power (instead of the amplitude) of a wave. Amplifiers increase the power of the electromagnetic energy by using special structures that carefully add voltage to the waveform without changing its frequency, which is a huge deal in the world of electronics.

There's only one problem: sometimes the machine can get a little too excited and use too much energy at once. The voltmeter helps the machine check itself before it wrecks itself by measuring the changing voltage or the changing energy potential. Think of a voltmeter as a power detector.

 

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(Now if we can just get the voltmeter to detect the potential for chocolate power. Mmm, chocometers.)

Then there's the analog to digital converter. An analog to digital converter converts voltage (measured in Volts) and transforms it to a number that is associated with the amplitude of the wave. That makes it much easier for all the other machines to communicate in the same measurement system.

Even though nothing could possibly go wrong from using different measurement systems, right?

Once you've got all that set up, you'll need an antenna. The antenna takes an alternating current signal and radiates the electromagnetic energy waves into the environment. Antennas can be very long and bulky or small and pocket size. If you want to pick up signals from far away and don't care about how much space that antenna takes up, you'll want a big and bulky one. If you want a small one you can put in your pocket (and occasionally pull out of your pocket like a wand), you're going to sacrifice the range your device can pick up. Antennas both create and receive electromagnetic fields, which is pretty nifty.

 

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Finally, we've got the duplexer. A duplexer lets an input signal and an output signal share a single antenna. That's the only reason an antenna can do both at the same time (well, that and the scientific theories that say it can happen). What's next, a triplexer to let the antenna balance a social life with all the work it does? Who knows?

And that's it. That's what you need to make a radar.