Fangrui Product Details Measurement Of Humidity, Humidity Sensor, Humidity Detection, With A Relay Output, Direct Power Control Equipment Using High-quality Hr202 Humidity Sensor; The Comparator Output Directly Drive The Relay, The 220v Ac Or Other Equipment; With A Potentiometer To Adjust Temperature Detection Threshold Sensor Interface Can Be Arranged Needle, With The Lead Of Humidity Sensor; The Circuit Board Size: 50x26mm, Thickness 19mm, With Four 3mm Fixing Bolt Holes, Easy To Install Contact Normally Open Circuit Connection: Functional Diagram Connection Is When The Relay Does Not Suck Timely ,publicend And Normally Closed Terminal Is Turned On, The Equivalent Of Switching Off, No Power Control Equipment Does Not Work, When The Relay Pulls In, The Public End And Normally Open Turning, Equivalent Switch Is Turned On, The Device Has Power To Work Contact Normally Closed Circuit Connection: Functional Diagram Connection Is When The Relay Does Not Suck Timely Public Side And Normally Closed Terminal Is Turned On, The Equiva