3.6 I'leasuingResistance-TheWheatstoneBddqe 71 3.6 Measuring Resistance-The Wheatstone Bridge Many difrerent circuit conJigurations are used to measue resistance, Heie we will locus on just one, the mealstone bddge. The Wheatstone brialge circuit is used to precisely measure resistances of medium values, that is. itr the range of 1 O to 1MO. In commercial models of tie Wheatstone bridge, accuracies on the order of +0.1olo are possible. The bridee circuit consists of four resislorr a dc voltage source. anl a delector.The ;sisraoce of one of the four rcsiston can be varied, wbich is indicated in Fis_ 3.26 bvlhe arrow tlu-ough Rr. Tbe dc \ohage source is usually a bartery, whicb is indicated by the battery symbol for the voltage source z, in Fig. 3.26. The detector is generally a d'Arsonval movement in the micioamD ranqe and iscaued a galvanometef. Hgure 3.2b sho\rs the circuil aflansemenl ot lheresislaoces baltery and detectof q bere Rt. R.
This is the end of the preview. Sign up
access the rest of the document.