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K6-33. Wheatstone Bridge


To demonstrate operation of a Wheatstone bridge.


Two 400 ohm resistors, 0-90 ohm variable resistor, 60 watt light bulb as "unknown" resistor, center zero 0-5 milliamp lecture meter, digital multimeter.

Setup Time

5 minutes.




A Wheatstone bridge is connected as in the circuit below using two (approximately) 400 ohm resistors, a 0-90 ohm variable resistor and a 60 watt light bulb (16.7 ohms cold) with a 6 volt battery and a 0-5 mA ammeter (large lecture meter). The unknown resistance Rx (the light bulb) is: Rx = Rs (R2/R1), where Rs is the resistance of the active part of the variable resistor (equal to the fraction of its length used multiplied by 90 ohms).

K. Electromagnetic Principles

K. Electromagnetic Principles

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