We developed this AC mains noise tester with reference to foreign products. It displays the current voltage value and noise voltage value of the mains through OLED dot matrix screen of its panel. In this way, you can see the current state of the mains power very intuitively, and you can repeatedly compare the changes in noise voltage between before and after the mains is used, and you can have a rational and accurate judgment on its effect. With this tester, it is easier for everyone to adjust power supplies to the best state, avoiding random spending on various power processing and failing to achieve a desired effect. Features: - OLED screen displays noise voltage value and AC voltage value - There being small speakers, it can directly amplify noise and output. The size and frequency of the noise can be roughly judged by sound to determine its source - Plug directly into a wall socket (power outlet) - Your speaker plays the sound of EMI and demodulates the amplitude to identify the source of EMI (e.g. AM or shortwave radio, electric motor and arc) Attention: The tester mainly measures the noise voltage in high frequency 10KHz-10MHz, and some power filters have no obvious noise filtering effect in this frequency band, and may even slightly increase noise voltage in this band. Therefore, the value measured by the tester is for reference only, and customers are required to comprehensively judge the effect of filters. Product Parameters: - Input voltage: AC 85Vac-250Vac 50/60Hz (accuracy +/- 1 VAC) - Frequency range: 10KHz-10MHz - Noise range: 1mV-1999mV - Measurement accuracy: +/- 5% at 1MHZ; +5% to -50% at 10 KHz to 10MHz - Noise indication: 4-digit yellow and blue OLED dot matrix display - Dimensions: 132 x 91 x 41mm/5.2 x 3.6 x 1.6" - Weight of whole machine: 150g/0.3 lb Package Included: - 1 x Line EMI Meter - 1 x AC Detachable Two-Core Power Cord 0.8M/2.6FT