基于电磁感应法的交变磁场测量电路设计

Design of Alternating Magnetic Field Measurement Circuit Based on Faraday Law of Electromagnetic Induction

为了测量交变磁场的磁感应强度,设计了基于法拉第电磁感应定律的测量电路。详细阐述了电路工作原理和设计思路,并分析了测量结果。由漆包线绕制的空心传感线圈感测到微弱的感应电动势,然后通过精密运放组成的前置放大电路和精密整流电路,得到有效值电压;经过比较整形电路,得到与感应电动势频率相同的方波信号。最后通过单片机AD采样和频率测量,可计算出交变磁场的磁感应强度。所设计的电路测量的百分误差在5%以内,测量结果准确,稳定性好,有一定的实用价值。

In order to measure the intensification of alternating magnetic induction,a circuit based on Faraday law is designed.The working principle and design idea of the circuit are described in detail.The measurements are analyzed.The weak induced electromotive force is sensed by the hollow pick-up coil which is wound by enameled wires,and is amplified by the circuit module which consists of precision operational amplifiers.Then one way of the amplified signal is sent to a precision rectifier circuit from which output the root mean square voltage.Another way of the amplified signal is transformed to square wave with the same frequency through a compare and shaping circuit.A microcontroller measures the root mean square voltage and the square wave frequency.It finally calculates the intensification of alternating magnetic induction.The measurement’s percentage error is less than 5%,The result shows that the circuit is precisely,reliably and valueable.