Anderson's bridge derivation - Phasor diagram - Advantages - Disadvantages

An Anderson bridge can measure low quality factor coils' inductance and resistance with high accuracy. The lower the Q-factor of the coil the more accurate the Anderson bridge will be.

Anderson bridge is a modification of Maxwell-inductance capacitance bridge and is known to be the most accurate bridge for the measurement of self – inductance over a wide range of values, from a few micro-Henries to several Henries.

Anderson bridge derivation :-

Note :- Transforming the delta  ECD to equivalent star is another way of finding the balance equation. Give it a try !!

From the above circuit diagram Anderson's bridge phasor diagram can be drawn as shown.

Anderson bridge advantages :-

(1) A fixed value capacitor is used  ∴ less costly bridge.

(2) Can be used for accurate measurement of capacitance in terms of       inductance.

(3) Easy to obtain balancing condition at low quality factor.

Anderson bridge disadvantages :-

(1) It is more complex  as compared to Maxwell's  bridge and                    therefore difficult to obtain balancing condition at medium and          high quality factor.

(2) Bridge cannot be easily shielded due to additional junction point        ,to avoid the effects of stray capacitances.

To summarise :- Use Hay's bridge for high Q factor coils, Maxwell's bridge for medium Q factor coils  and Anderson's bridge for small Q factor coils.


Closely Related :-
(1) Hay's Bridge
(2) Maxwell's Bridge
(3) Owen Bridge
(4) AC Bridge Basic Theory

Related :-
(1) Schering Bridge