The power consumption of ACEL panel is usually measured by a bridge circuit shown in Fig.1.However

it is suitable only in a limited range.In some

it is found in the experiments that:1)the measured value of power consumption car.es depends on the resistance R in the circuit;2)The measured total power consumption when several panels are connected in parallel is smaller than the sum of the power consumption of these panels measured separately.Analysis has shown that this circuit is only suitable for the panels whose resistance is very high and whose capacitance is very low.In addition

the nonlinear nature of the ACEL panels causes larger experimental error.A improved bridge circuit for measuring the power consumption is designed in this paper.Monitoring the change of the phase difference and current

we can easily adjust both the compensation resistor and capacitor to bring the bridge to the equilibrium.Then the resistance of the panel can be determined directly.The new method overcomes the problem mentioned above and has higher sensitivity and precision.Also the nonlinear nature of the panel has little influence for the result of the measurement.