Laser detector adopts special laser and receiving device, and its receiving device is highly sensitive. It is particularly sensitive to interference from the power grid, human body and light. YUWEI portable laser counterfeit detector used in the design of low voltage circuit special grid interference circuit, it can work stable output equipment, power supply and the city power grid disturbance signal disconnect from the essence, eliminate the interference from the municipal power grid and the human body electrostatic interference. In the signal circuit, frequency selection and filtering are used to further enhance the anti-jamming capability of the instrument. Therefore, YUWEI portable laser detector can work in a very bad environment. Even in June, the high temperature of the sun can accurately test paper money.