... company past Certificate of CE and ISO9001; frequency meter Product Specification:JYX-45-HZ Frequency meterOutline Size:50*100*66mm Hole cutour ... -500V,above 500V should concect the current transformerXXX/100V.4.Frequency meter , sampling AC voltage signal input value,(110V-380V), i ... .e. display the frequency value of the voltage,the dispay range of frequency is 30.0Hz-99.9Hz5.Technical ...