## Measurement of Capacitance By DeSauty's Bridge:

**DeSauty's Bridge**is the simplest method of comparing two

**capacitances**.The connections and the phasor diagram of

**DeSauty's Bridge**are shown in the below figure.

Let C1 = capacitor whose

**capacitance is to be measured**,
C2 = a standard capacitor, and

R3, R4 = non-inductive resistors.

The balance can be obtained by varying either R3 or R4.The advantage of

In order to make measurements on imperfect capacitors (i.e., capacitors having dielectric loss),

**DeSauty's Bridge**is its simplicity.But this advantage is nullified by the fact that it is impossible to obtain balance if both the capacitors are not free from dielectric loss.Thus with**DeSauty's Bridge**only loss-less capacitors like air capacitors can be compared.In order to make measurements on imperfect capacitors (i.e., capacitors having dielectric loss),

**DeSauty's Bridge**is modified as shown in the below figure.This modification is due to Grover.
The balance may be obtained by variation of resistances R1, R2, R3, R4.The above figure (b) shows the phasor diagram of the

**DeSauty's Bridge**under balance conditions.The angles δ1 and δ2 are the phase angles of**capacitors**C1 and C2 respectively.
Dissipation factors for the capacitors are :

D1 = tan δ1 = ωC1r1 and

D2 = tan δ2 = ωC2r2

Therefore, if the

These quantities are moderately large and their difference is very small and since this difference cannot be known with a high degree accuracy, the

In this, we have learnt

**dissipation factor**of one of the capacitors is known, the dissipation factor for the other can be determined.**De Sauty's Bridge**does not give accurate results for dissipation factor since its value depends on difference of quantities R1R4/R3 and R2.These quantities are moderately large and their difference is very small and since this difference cannot be known with a high degree accuracy, the

**dissipation factor**cannot be determined accurately.**Conclusion:**In this, we have learnt

**Measurement of Capacitance By De Sauty's Bridge**.You can download this article as pdf,ppt.If you have queries you can email us @ palakalaamarnath@gmail.com.**Comment below if you have any queries!**
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