Based On Type Semiconductor Thin Film Magnetoresistive Element Study Of The Current Switch

The technology of sensors is one of crucial components of the modern information technology. Sensors are the interface of the studied object and the information system, and also the access of the system to acquire and detect information. Magnetic sensors are one of important branches. The magnetoresistive current switch (MRCS) in this paper is designed for the fine measurement and detection of the current at 50Hz . Through the sensor, it can convert the current signal into electric pulse signal, i.e. digital logic electric level.Firstly, the paper introduces the theory of the inSb magnetosensitivecharacteristics. And then analyzes in detail about the structure principleof magnetoresistive current switch (MRCS). Its circuit structure is mainlyconstituted by three units: Signal-processing circuit , the comparatorcircuit unit and driving circuit unit.By improving the frequency pass band , a new signal-processing circuit was designed to ensure the frequency range of from 47 Hz to 53 Hz. It is based on the traditional coupling circuit using capacitance and resistance.. As a result, this signal-processing circuit can realize the detection of the current signal at 50Hz .Eventually, it inhibited the non-standard signal while preventing the switch from operating by error. Moreover, in the comparator circuit unit, we realize the function -the detection of the number of positive and negative electric pulse.Lastly, we design the applications system of single-chip microcomputer, counting the number of MRCS output electric pulse .The main function of system is to measure the number of pulse, i.e. the detection of digital quantity. The circuit designs of two units eventually realize the detection of the current at 50HzFinally, the electric characteristics and performance of magnetoresistive current switch (MRCS) are tested.1 , Test the two groups of MRCS samples.When the work frequency AC increased from 10mA to 100mA, the output voltage of the first group rised approximately linearly from 1.5V to 3.5V; the output voltage of the second group rised approximately linearly from 1.8 V to 4.5V. In a conclusion, the results indicated that MRCS possessed excellent linearity.2, The design filter's central frequency is 49 Hz. Two cutoff frequency 46.5 and 52.7 Hz choose the bandwidth of 6.2Hz. Thus, basically achieve the purpose of passing the work frequency current.3, The comparator circuit unit puts out pulse which in 0.1 second accounts to 10 i.e. the siginal's frequency is 100Hz.