Most modern day electronics now use printed circuit boards and highly integrated circuits.
Health and environmental concerns associated with electronics assembly have gained increased attention in recent years due to the use of hazardous materials in the manufacture of various electronics: Components, Printed circuit board manufacturing, Surface-mount device (wave soldering and selective soldering), Case-up, Functional Testing in a range of conditions (temperature, humidity, vibrations, strain, etc.), Cleaning and Drying, Testing.