electricalperson
Senior Member
- Location
- massachusetts
does anybody here have a good wiring diagram and instructions on how to build a wheatstone bridge?
does anybody here have a good wiring diagram and instructions on how to build a wheatstone bridge?
Out of curiousity, why? Kelvin bridges are much more accurate and not much harder to build. What are you planning on doing with this?
You do know you can buy these pretty cheap right?, they are disguised under other names. In fact, many people own them and dont even know it.
i was reading about one in a book and i want one to experiment with. i have no idea what a kelvin bridge is and i dont know what they cost or disguised as
090107-1938 EST
electricalperson:
Get a 1 turn linear potentiometer, or better yet a 10 turn helipot. 1000 ohms is suitable. A 12 V battery. Put a 220 ohm 1 W resistor in series with the battery to serve as a current limiter if you do something wrong. Get an assortment of resistors from 100 ohms to 10,000 ohms. Possibly 100, 220, 470, 1000, 2200, 4700, and 10,000. Also get one extra 100, 1000, and 10,000 ohm 1 W resistor.
You need a meter that is sensitive to millivolts.
I will continue a little latter. Tell me what you have to work with.
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You can get everything from Radioshack, although it is a little more expensive than mail order.
However, I don't see why all the parts would cost more than $10 even from RS.
And you should be able to get a cheap meter for $10-$20 bucks, if you already don't have one. Although, if you are interested in electricity, I would suggest spending enough to get a good meter. And for bridge experiments, you really need a meter that measures both positive and negaitve currents or voltages.
Also, buy a photoresistor, and try using that as one of the resistors in the bridge as you vary the light levels. You can detect really small changes in light level like this.
That should work fine. Although IMO, wheatstone bridges are a little more fun if you have a panel type meter (the analog meters where the needle rests in the middle of the scale, and can swing in either direction.)