A threading circuit resistance tester is designed using STM32 MCU as the main controller. The tester generates 1 000 Hz sine wave by ML2035 module

after power amplification

the signal is added to the voltage coil

which generates magnetic field with the same frequency

by the loop through the voltage coil

the magnetic field induces loop current and generates an alternating magnetic field with the same frequency. The current signal of the same frequency is generated by the magnetic field generated by the current coil through the induction loop current.Through collection of the loop voltage and current

loop resistance can be measured. The experimental results show that the designed measurement system operates stably

it is convenient to install

measurement precision is high

it can transmit data accurately

on-line monitoring can be realized

and it has high application value.