A transistor is a semiconductor device used to amplify or switch electronic signals and electrical power. It is composed of semiconductor material usually with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current through another pair of terminals. Because the controlled (output) power can be higher than the controlling (input) power, a transistor can amplify a signal. Today, some transistors are packaged individually, but many more are found embedded in integrated circuits.
Some of the earliest work on semiconductor amplifiers emerged from Eastern Europe. In 1922-23 Russian engineer Oleg Losev of the Nizhegorod Radio Laboratory, Leningrad, found that a special mode of operation in a point-contact zincite (ZnO) crystal diode supported signal amplification up to 5 MHz. Although Losev experimented with the material in radio circuits for years, he died in the 1942 Siege of Leningrad and was unable to advocate for his place in history. His work is largely unknown.
Austro-Hungarian physicist, Julius E. Lilienfeld, moved to the US and in 1926 filed a patent for a “Method and Apparatus for Controlling Electric Currents” in which he described a three-electrode amplifying device using copper-sulfide semiconductor material. Lilienfeld is credited with inventing the electrolytic capacitor but there is no evidence that he built a working amplifier. His patent, however, had sufficient resemblance to the later field effect transistor to deny future patent applications for that structure.
<span>German scientists also contributed to this early research. While working at Cambridge University, England in 1934, German electrical engineer and inventor Oskar Heil filed a patent on controlling current flow in a semiconductor via capacitive coupling at an electrode – essentially a field-effect transistor. And in 1938, Robert Pohl and Rudolf Hilsch experimented on potassium-bromide crystals with three electrodes at Gottingen University. They reported amplification of low-frequency (about 1 Hz) signals. None of this research led to any applications but Heil is remembered in audiophile circles today for his air motion transformer used in high fidelity speakers.</span>
When its temperature increases, the reactants have more kinetic energy so the frequency of effective collision increases, resulting in a faster rate of chemical reaction.
Answer:
3.59 m/s
Explanation:
The average velocity is defined as:
The turtle first walks 18m south, and then is taken 1,1Km (or 1100m) north. Thus, the total displacement is 1082m north (1100m north - 18m south).
Now we have to calculate the total time, which will be equal to the sum of the time the turtle walked and the time it was taken by truck.
The walking time is 3.5 minutes. Since 1 minute = 60 seconds, then the walking time is 210 seconds.
To calculate the truck time we use the equation:
Time =
Where the distance the truck travelled is 1100m and the speed of the truck is 12m/s.
Thus,
Truck time= = 91.67s
The total time is the sum of the walking time and the truck time.
Total time = 210s + 91.67s = 301.67s.
As mencioned previously, the average velocity is equal to total displacement/ total time, thus:
Average velocity = = 3.59 m/s North
Since the average velocity is a vector, it has a magnitude and a direction. In this case the magnitude is 3.59 m/s and the direction is north since the turtle's final displacement is north of where it started.