How Electrical Components Function
...the most common and cheapest resistor. The example of variable resistors is the potentiometer, which we could use to adjust the amount of current flowing through by rotating the bar at its center. In fact, we use the potentiometer very often in the lab to adjust things such as the speed of a flashing LED or the pitch of the speaker. The capacitor is a device with two legs. It has a positive and a negative electrode. Its main function is to store electricity or electrical energy. When the capacitor is charged up, the current flows. The current will stop flowing when the capacitor has been fully charged. Each capacitor has the maximum amount of voltage that can be used. When the voltage has exceeded the maximum amount, it will cause the insulator inside the capacitor to break down and conduct, thus blasting and causing danger. Large values of capacitance can be obtained in comparison with the size of the capacitor. Mostly, the amount of capacitance in capacitor we see is pretty small. For example, when we unplug the power supply, the LED will stay on for a few more seconds because the capacitor in the circuit has stored some electricity. The transistor is also called “amplifier”. There are three legs in a transistor, E, B and C. E stands for “emitter”, B for “base” and C for “collector”. The function of the transistor is to amplify the electric current. In others words, the transistor can boost a weak input current till it reaches the required amount of the circuit. The transistor has replaced the thermionic valve because it is smaller, stronger and can last longer. Electronic amplifiers are used in radio and television transmitters and receivers, audio and stereo systems, intercoms, and many other consumer electronics devices. There are many kinds of diodes. A diode is a semiconductor device that allows electrical current to flow through it in only one direction. The symbol is used to indicate a diode in a schematic diagram. While the anode is at the left side of the symbol, the cathode is at its right. The current flows from the anode side to the cathode side. Currents flow through the direction where the arrow in the symbol is pointing. In the lab, the circuit will not work if we flip the diode around, because it will not allow the current to pass thought along the opposite path. In addition, there is a kind of diode called LED (light emitting diode). There are various kinds of colors. Alternate colors can be chosen; the most common colors are red green and yellow. An LED has two legs: the longer one is the anode (positive) while the shorter one is the cathode (negative). The LED is widely used throughout the globe. For example, LED lamps are used in traffic signals and pedestrian lights. Although the initial cost to buy an LED is higher than a standard incandescent bulb, the LED lasts more than 12 times longer and uses up to 90 percent less...