For a physics lab, we have much too efficient of capacitors, and we have calculated that we need an approx. 4000 ohm resistor in our circuit. Any ideas on a resistor we could use? (Tried a pencil, thought it worked, but we were wrong. It didn't)
2007-02-28 05:29:26 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Physics
If you needed to obtain an actual resistor, you could buy one at an electronics store such as Radio Shack (they're quite inexpensive); the closest standard value is 3900 ohms. If you want to try to make one, take a piece of cardboard, put two holes in it for small bolts, and connect the holes with a fairly broad pencil line. Attach wires with bolts, nuts, and washers; the pencil line will conduct some electricity and you can experiment to see how much resistance the pencil line provides. It is worth while using an ohmmeter to help monitor this process; you can get a nice digital ohmmeter from Harbor Freight Tools for less than $10. (The last one I bought was on sale, and it cost me $3.)
2007-02-28 05:42:06 · answer #1 · answered by Anonymous · 0⤊ 0⤋
If you need it immediately, perhaps you could calculate the resistance of some other objects in the lab using resistivity. The link at the bottom has resistivities of some common materials.
If you have time, just run down to Radio Shack. Resistors are cheap, and they'll probably have one in stock.
If you get really desperate, find an old telephone or something and crack it open. You can cut out some of the resistors, and using a multimeter, check the resistance of each (or you can look at the color bands). From those, hopefully you can place the resistors in series or parallel to come up with something you can use.
2007-02-28 05:36:09 · answer #2 · answered by wheresdean 4 · 0⤊ 0⤋
Run down to the cafateria and grab a lemon or potato and you can " Use It " as the resistor in your circuit, but I believe they have high resistance ( I forget though). You should check them out, a lime may be better because of the citrus acid ( chemical reaction).
I think though, you can buy like a pack of 6 resistors at most electronics stores ( Radio Shack included) for about $0.55 USD, so they really are of high quality and very little investment.
2007-02-28 06:08:53 · answer #3 · answered by Anonymous · 0⤊ 0⤋
Go to Radio Shack and buy one. You'll have to settle for 3900 Ohms though, because 4000 Ohms is not a standard value.
If there is no Radio Shack nearby, try the Electrical Engineering college. One of their labs will have all the resistors you need, and they might just give it to you, free.
.
2007-02-28 05:38:52 · answer #4 · answered by tlbs101 7 · 0⤊ 0⤋
Place in series :
1 resistor 3.3kohms
1 resistor 680 ohms
1 resistor 22 ohms
The total is 4002 kilohms. You should pay attention to the resistor tolerance and the watts.
The above values of resistors are common in the market.
2007-02-28 06:05:04 · answer #5 · answered by Alice in Wonderbra 7 · 0⤊ 0⤋
You can buy ceramic resistors (look for 4K designation).
2007-02-28 05:37:10 · answer #6 · answered by Swamy 7 · 0⤊ 0⤋