Resistors
Hello friends after a long time welcome back .In this post we will basically discuss about the resistors. Limiting Power with Resistors The main water supply hookup to your home is a fairly large pipe. But the pipe leading to your shower head is a lot smaller. Obviously, the smaller pipe saves some space, but it also acts to decrease the amount of water delivered to that location. You would not be pleased to begin your day with a shower blasting you with the full force of your water main! (Well, I don’t know you personally; perhaps you could use that much of a shower.) Besides the displeasure of getting overwhelmed by a watery blast, a lot of water would get wasted. You don’t need that much water to effectively take a shower. Resistors limit or divide up the flow of electricity. In doing so, they prevent waste and deliver the specifically requested amount of electricity to each part. Understanding Size and Tolerance 5% tolerance means that a 100 ohm resistor could be as low as 95 ohm or as high as 105 ohm. That’s plenty accurate for home made robots. You can spend a little more money and purchase 1% tolerance metal-film resistors, but your robot isn't going to notice the difference. Many of the high-precision resistors have more than four colour bands, which makes it more difficult for a beginner to decipher the value. Measuring Resistance We are not discussing this topic here since we all know how to measure resistance using colour coding method. If you really wan't to learn then comment in our comment box we will surely discuss on that next time. | Variable Resistors Potentiometers Potentiometers are variable resistors. Their resistance changes by turning a control knob or dial. You’ve probably operated potentiometers plenty of times without even knowing it. For example, potentiometers commonly control stereo volume as well as analog television brightness and contrast. You can adjust all potentiometers down to zero ohms (no resistance). The value printed on the potentiometer indicates its maximum value. For example, you can adjust a 500 ohm potentiometer from 0 ohm up to 500 ohm. You can adjust a 10 kohmΩ potentiometer from 0 ohm to 10 kohm. There are a wide variety of potentiometer sizes and packages available. However, like switches, only a small subset of potentiometers fit into a solderless breadboard. The other potentiometer sizes tend to have oddly spaced or thick leads Cadmium-Sulfide Photoresistors Cadmium-sulfide photoresistors are extremely popular in robotics. They’re lightweight, inexpensive, fascinating to look at, and mimic the visible-light responsiveness of the human eye. Cadmium-sulfide can be abbreviated CdS. Sometimes, photo-resistors are called photocells or photo-conductors. It’s the same component no matter the name. Potentiometers change resistance in response to rotations of their dials, whereas photo-resistors change their resistance in response to the amount of light shining on them. Pretty cool! |