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# 13.9B: The Schering Bridge

This bridge can be used for measuring capacitance.

FIGURE $$\text{XIII.10}$$

The admittance of the fourth arm is $$\frac{1}{R_4}+jC_4\omega$$, and its impedance is the reciprocal of this. I leave the reader to balance the bridge and to show that

$\tag{13.9.6}\frac{R_1}{R_2}=\frac{C_4}{C_3}$

and

$\tag{13.9.7}C_1=\frac{C_3R_4}{R_2}.$