<P> An electronic cigarette is a battery - powered vaporizer . The primary parts that make up an e-cigarette are a mouthpiece, a cartridge (tank), a heating element / atomizer, a microprocessor, a battery, and possibly a LED light on the end . An atomizer comprises a small heating element that vaporizes e-liquid and wicking material that draws liquid onto the coil . When the user pushes a button, or (in some variations) activates a pressure sensor by inhaling, the heating element then atomizes the liquid solution The e-liquid reaches a temperature of roughly 100 - 250 ° C within a chamber to create an aerosolized vapor . The user inhales the aerosol, commonly called vapor, rather than cigarette smoke . The aerosol provides a flavor and feel similar to tobacco smoking . </P> <P> There are three main types of e-cigarettes: cigalikes, looking like cigarettes; eGos, bigger than cigalikes with refillable liquid tanks; and mods, assembled from basic parts or by altering existing products . As the e-cigarette industry continues to evolve, new products are quickly developed and brought to market . First generation e-cigarettes tend to look like tobacco cigarettes and so are called "cigalikes". Most cigalikes look like cigarettes but there is some variation in size . Second generation devices are larger overall and look less like tobacco cigarettes . Third generation devices include mechanical mods and variable voltage devices . The fourth generation includes Sub ohm tanks and temperature control devices . The power source is the biggest component of an e-cigarette, which is frequently a rechargeable lithium - ion battery . </P>

What is the top part of an e cig called