Such protection of the electromagnetic coil is not to be underestimated, it plays an important role in our life. Today, I explained to you by a small series, the background technology is currently, the public can save the power of the electromagnet and the protection of the coil due to heat damage to the electronic products have the characteristics of small, poor reliability. There are two reasons, one is the power device fever led to premature failure, the two is affected by the characteristics of the stability of the stability of the poor. In order to overcome the disadvantages of the prior adaptation surface and the poor reliability, the utility model provides an electronic product which can make the electromagnet save electricity and can protect the coil from heating. The beneficial effect of the utility model is: in the existing process loops access the controller does not change the original electromagnetic coil operation characteristics, do in electricity to maintain state power down to a few percent of the original, the realization of the energy-saving and reduce the electromagnetic heating coil.