Soldering terminology

Surface temperature at which dew drops appear on a body cooling in air. If components cool down overnight in a factory building with highly humid atmosphere, water may condense on their surface and hinder the soldering or lead to the formation of blow holes. Therefore, the parts to be soldered must first be dehydrated by heating. The air coming in contact with the body is saturated with water vapor and the partial pressure of the water vapor corresponds to the saturation vapor pressure at the dew point. Air humidity can be determined using a dew point hygrometer which measures the temperature at which a metallic mirror fogs up while gradually cooling down.