The Choice of AC Electricity Bridge Adjustment Parameters

It is set forth that how to choose adjustment parameters in the plural plane coordinate figure by the relation of Electricity Bridge’s balance condition and adjustment parameters.


The Balance Condition of AC Electricity Bridge
The balance process of AC electricity bridge is decided by the change of eqn(1) .Because Z 1 Z 2 ,Z 3 ,Z 4 are composed of resistance,apacitance and inductance which are parallel connection or in series,xcept the observed parameters, the others quantities can be regarded as adjustment parameters.
It is shown by eqn(1) that the two quantities at least are chosen as adjustment parameters for a and b=0 together.If three or the more quantities are chosen,hen adjustment times is nimiety,he balance process can be very much trouble.In the most things, two quantities are chosen as adjustment parameters.
The selections have more groups.Some groups can not attain the balance of electricity bridge;some groups may attain the aim,but nimiety.It is the best choice that not only some groups may attain the balance but also the adjustment times are few.The article will set forth how to choose correct adjustment parameters quickly through the frequent used AC electricity bridge.

The Quickly Chosen of AC Electricity Bridge Adjustment Parameters
At the balance point of electricity bridge,the relation of a,b and adjustment parameters may be expressed by parallel beeline family [3] .The more nearly 90 0 of two parameter beeline angle, the more quickly of balance speed.It can be shown that which parameter beeline are perpendicularity or parallelism one another.The best choice is two parameters of perpendicularity, not parallelism.Without parameters of perpendicularity, the best seemliness choice is two parameters which angle is rather big.

Capacitance Electricity Bridge
According to Fig. 2,it is shown the expression formula of a and b are eqn(2) and eqn(3) separated by the eqn(1).The beelines of each parameters are shown in Fig. 3.It is the best choice that R 2 and C 2 are adjustment parameters ,as shown in Fig. 3.

Inductance Compare Electricity Bridge
According to Fig. 4,it is shown the expression formula of a and b are eqn(4) and eqn(5) separated by the eqn(1).The beelines of each parameters are shown in Fig. 5.It is the best choice that R 2 and L 2 are adjustment parameters ,as shown in Fig. 5.

Schering Electricity Bridge
According to Fig. 6,it is shown the expression formula of a and b are eqn(6) and eqn(7) separated by the eqn(1).The beelines of each parameters are shown in Fig. 7.Because the angle of R 3 and C 3 is rather big,it is the best choice that R 3 and C 3 are adjustment parameters ,as shown in Fig. 7.

Maxwell Electricity Bridge
According to Fig. 8,it is shown the expression formula of a and b are eqn(8) and eqn(9) separated by the eqn(1).The beelines of each parameters are shown in Fig. 9.Because the angle of R 3 and C 3 is rather big,it is the best choice that R 3 and C 3 are adjustment parameters ,as shown in Fig. 9.
For the complex AC Electricity Bridge, it is difficult to ascertain the relation which a and b change with some parameter varying.At the time ,it may be judged by the software of origin.

Conclusion
First, the each parameters are done in the coordinate chart of a and jb,then according to the angle between the beelines,it is a convenience method to choose perpendicularity or bigger angle as the adjustment parameter.