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# Trying to explain a curciut with current or Ohm's Law.

Posted Oct2-09 at 12:08 AM by Integral

The students build a simple circuit consisting of a battery, resistor and LED. Frequently the circuit does not work, therefore it is necessary to help the students find the problem. Since Ohm's Law and even the concept of current has not yet been presented I find it very difficult to explain, for example, why when a 1M Ohm resistor is used instead of a 100 Ohm the LED does not work.

I am convinced that the sooner you get all the basic concepts, voltage, current, and resistance in front of them and tied together with Ohm's Law the better. Then each lab can explore Ohm's Law and meaningful troubleshooting techniques can be taught.

Math class is mostly lecture, I was pleasently surprised to LEARN something in the lecture. I did not realize that if the digits of a number sums to 3 or a multiple of the 3 that the number is a multiple of 3. This has to be true because 3 is the sqrt of 9 so therefore inherits some special properties for being closely related to the largest integer.

I like the spirit and attitude of the Math teacher. Today I really admired her problem selection. They were given a set of problems finding the constant difference in a sequence of numbers, then finding the next 3 terms in the sequence. The last problem how ever was different. She threw the Fibonacci sequence. I doubt any of the students found the pattern without help but I enjoyed helping them find the solution.
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1.  That's weird that students have not yet learned about current in the circuits class. I would have thought any understanding of electronics is predicated on having an idea of what voltage and current are. Posted Oct3-09 at 06:51 PM by Redbelly98
2.  when describing ohms law i relate it to the flow of water in a water pipe. ie low resistance =fat pipe low voltage = low pressure so a fire hose has high pressure-high voltage- reasonably low resistance and large quantity of water-- watts used and very high pressure-water cutting tool - equals static voltage with destructive power but very little -watts Posted Oct10-09 at 04:26 PM by piersdad
3.  v=ir, it is all what you explained??? circuits are not that much difficult my dear.. Posted Oct16-09 at 07:04 AM by sridharsharma
4.  please send me derevation of OHM's law Posted Jan11-10 at 08:16 AM by khizar