Laurie Jones and Diala Al Shamasneh FM TRANSISTOR RADIO Laurie Jones and Diala Al Shamasneh https://commons.wikimedia.org/wiki/File:Homemade_High_Quality_FM_stereo_radio_receiver.jpg http://elect.wikispaces.com/CD2003+-+yet+another+simple+FM+radio+receiver

RADIOS IN HISTORY!!!! Edwin H. Armstrong invented FM broadcasting 1933 and he even started his own station in 1939 to show that it is actually useful (Britannica).  Radios were not really portable at that time. The first commercial transistor radio was "the Regency TR-1 [which] hit stores on October 18, 1954… Roughly a decade later, they added FM capabilities, and ever-cheaper import models flooded the markets" (Smithsonian).  Currently FM radios are not really common except in vehicles, and even in cars, people can choose to listen to music on demand by connecting a mobile device. Since most people can listen to the radio on their phones, or better yet, choose their own music to listen to without all the ads on the radio, its popularity has declined. The radio itself will probably become obsolete    in the future as more and more people prefer     streaming. Just a picture of a radio I found in my great-aunt's house. It's built in with the furniture!!

WHY SHOULD I CARE ANYWAY???? I remember my grandfather sitting every day at noon on the ground, tuning his hand held radio to get to the news station, putting it two inches away from his ear, and listening to it for an hour whenever we visited him in the summer. Then, whatever news he heard would be the topic of conversation among the adults. Because I did not really grow up with a radio in the house or one in the car (it was an old model), I did not really understand what was going on. It did not have a huge satellite dish like the TV did so it was pretty strange at the time. A decade or so later, I get to explore what actually made his radio work, so why not?

Challenge and model The mystery will probably be how to make the coil in order to get a certain frequency. The length and diameter are important for this. The coil would be the inductor and along with a capacitor, they tune the radio. Our model will probably be a very simplified radio with one station to listen to. It will be done on one of the bigger boards available and everything will be labelled to make sure the viewer can easily see and understand what is going on. Picture: https://electronics.stackexchange.com/questions/171739/will-four-wires-work-for-crystal-radio-coil 

How does it work? A radio is a receiver for the radio waves that are traveling through the air. Projecting from a radio tower, as many have seen, radio waves can be manipulated to hold radio stations in two ways. The one we are concerned with is where one can add a carrier to the wave so that there will be certain fluctuations in the frequency of the waves. This is called frequency modulation and is where we get the term FM from Using the voltage from the battery that we will have, and then going through some various capacitors and amplifiers, the antenna. The tuning of the antenna causes the antenna to vibrate at various different frequencies and that is how it picks up the stations.  The antenna creates a current that corresponds to the radio signal. This current is sent to all the other parts of the radio to be filtered and amplified, to finally get to the speaker  This sounds more complicated than AM which picks up different amplitudes but actually a lot of interference comes in, making the amplitude change so the frequency actually is a lot better than AM for clear music and sound.

What are the Components? Resistor: basically "slows" the current that is going through the wires at this moment and makes them more clear Coil/ inductor: how many turns the coil has determines the frequency Amplifier: in a way "boosts" the waves that are coming through Transistors: this registers the frequency from the antenna and helps to send it to the speaker. It is kind of like a switch. speaker Capacitors: help store electric charge Picture: http://www.electroschematics.com/5150/tiny-fm-radio/

What are the concepts based on? Waves!!! Radio waves are just like the light waves we've studied except the wavelengths are MUCH bigger. This is how they are able to be picked up by the antenna Resonate frequency We learned about this previously but when two waves come together the amplitude of that wave increases tremendously. However in a circuit this means that a special frequency is reached based off of capacitors, resisters, and  inductors RLC resonate frequency According to a professor at Georgia State University this is when, " the inductive and capacitive reactances are equal in magnitude but cancel each other because they are 180 degrees apart in phase". Transistor is  a big one. Already defined in the last page, it acts like a switch. Once the antenna begins to ressonate it turns on and helps to direct the power toward the headset. Click to add text

Equations/Diagrams/specific theoretical basis resonate frequency or LRC resonate frequency Transistor Conductor equations (that we know)- Kirchoff's Law V (r) = IR V (c)= q/c V (l)= L dl/dt LRC Circut V(l) + V (r) +V (c) = V (t)

Bibliography https://www.britannica.com/biography/Edwin-H-Armstrong https://www.britannica.com/biography/Edwin-H-Armstrong  This has a short biography of Edwin H. Arrmstrong. https://www.smithsonianmag.com/smithsonian-institution/the-transistor-radio- launches-the-portable-electronic-age-110761753/ This gives a brief history of the first radios. http://www.explainthatstuff.com/radio.html This helped us get a good idea on what the basics of radios are https://www.youtube.com/watch?v=VmNlDewXt2M  This is a video of someone building the radio. He identifies all of the different parts of the radio https://www.livescience.com/46021-what-is-a-transistor.html Helped to reveal what a transistor is http://hyperphysics.phy-astr.gsu.edu/hbase/electric/serres.html Helped with resonance and the RLC resonance- this is a pdf from the physics department at Georgia State University