1-24With the ac signal applied to the bridge, R1 and R2 are varied until a zero reading is seen on themeter. Zero deflection indicates that the bridge is balanced. (NOTE: In actual practice, the variables areadjusted for a minimum reading since the phase difference between the two legs will not always allow azero reading.)CAPACITANCE BRIDGE.—Because current varies inversely with resistance and directly withcapacitance, an inverse proportion exists between the four arms of the bridge in figure 1-7; the right sideof our expression is inverted from the resistance bridge expression as follows:orFigure 1-7.—Capacitance bridge.Q-18.What effect does an increase in capacitance have on a capacitor’s opposition to current flow?Because R1 and R2 are expressed in the same units, the equation R1/R2 becomes a simplemultiplication factor. This equation provides a numerical value for C_{x} and will be in the same units as C_{s}(farad, microfarad, and so forth).

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