Maxwell Bridge

143

02:24:04

Measure unknown RL (top left) by varying two resistors (bottom left and bottom right) independent of frequency.  Diagonal voltage (measured with voltmeter) must be zero.

Names of elements:
.   .   .   .   .   .   .
Rx                    .
Lx                    R3
.                        .
.                        .
.                        .
R2                   R4
L2                     .
.   .   .   .   .   .    .


Computation of unknown elements:
Zx / Z2 = Z3 / Z4
Zx = Z2 * Z3 / Z4
(everything on the right must be known!)

...some steps in between...

Rx = R2 * R3 / R4
Lx  = L2 * R3 / R4

Problem: In practice, it is very difficult to find right resistor values such that amplitude AND phase of the diagonal voltage is zero. You could e.g. use an oscilloscope in xy mode for that.

published 7 years ago

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