Construction of electronic cigarettes

Function An e-cigarette is a handheld battery-powered vaporizer that simulates smoking, but without tobacco combustion. The different kinds of trigger sensor or sensors used are acoustic, pressure, touch, capacitive, optical, Hall Effect or electromagnetic field. E-cigarettes do not turn on by trying to "light" the device with a flame. A glycerin-only liquid vaporizes at a higher temperature than a propylene glycol-glycerin liquid. E-cigarettes are also used by some people as a smoking cessation aid. A Cochrane review found that nicotine e-cigarettes can help people stop smoking and may be more effective than nicotine replacement therapy and this use is supported by public health guidance in England. Some users also use electronic nicotine delivery systems (ENDS) to vape cannabis products, including cannabidiol (CBD) or tetrahydrocannabinol (THC) oils and e-liquids that are compatible with ENDS devices. Some people use e-cigarettes while continuing to smoke conventional cigarettes(“dual use”), for example during quit attempts or in situations where smoking is restricted. In the United Kingdom, guidance from the National Institute for Health and Care Excellence notes that, as of February 2025, no nicotine-containing e-cigarettes were licensed as medicines for smoking cessation by the Medicines and Healthcare products Regulatory Agency, and products not licensed as medicines cannot be marketed by manufacturers for stopping smoking; however, UK public health guidance distinguishes between the harms of combustible tobacco use and the use of smoke-free nicotine products, noting that vaping is less harmful than smoking and may support smoking cessation when smokers switch completely. Perception Vaping is different from tobacco smoking, but there are some similarities with their behavioral habits, including the hand-to-mouth action and a vapor that looks like cigarette smoke. The volume of vapor created by e-cigarette devices in 2012 declined with vaping. Larger percentages of glycerin in e-liquid also increase vapor production. == Construction ==

E-cigarettes come in many variations, Some e-cigarettes look like traditional cigarettes, but others do not. 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. Most versions are reusable, though some are disposable. They range in cost from under $10 to over $200. An entry-level reusable e-cigarette costs around $25. Disposable e-cigarettes are discarded once the liquid in the cartridge is used up, while rechargeable e-cigarettes may be used indefinitely. Even with rechargeable cigarettes (pod-based systems), there is a risk of littering. There are thoughts on how to prevent pods from ending up in the environment (i.e. a deposit-system for e-cigarette pods). One piece devices are normally disposable. A disposable e-cigarette lasts to around 400 puffs. Reusable e-cigarettes are refilled by hand or exchanged for pre-filled cartridges, and general cleaning is required. A wide range of disposable and reusable e-cigarettes exist. Disposable e-cigarettes are offered for a few dollars, and higher-priced reusable e-cigarettes involve an up-front investment for a starter kit. The LED is not generally used in personal vaporizers or mods. First-generation e-cigarettes usually simulated smoking implements, such as cigarettes or cigars, in their use and appearance. Later-generation e-cigarettes often called mods, PVs (personal vaporizer) or APVs (advanced personal vaporizer) have an increased nicotine-dispersal performance, They contain silver, steel, metals, ceramics, plastics, fibers, aluminum, rubber and spume, and lithium batteries. A growing subclass of vapers called cloud-chasers configure their atomizers to produce large amounts of vapor by using low-resistance heating coils. This practice is known as cloud-chasing. Many e-cigarettes are made of standardized replaceable parts that are interchangeable between brands. A wide array of component combinations exists. Many e-cigarettes are sold with a USB charger. E-cigarettes that resemble pens or USB memory sticks are also sold for those who may want to use the device unobtrusively. The increasing numbers of new vaping products combined with unrelated functions attest to a clear trend toward customization of e-cigarettes. It seems that experienced users like to adopt the e-cigarette to their (inhalation) needs, leading to e-cigarettes with adjusted airflow inlet using atomizer heads with different sized air holes. This is applied in the most recently introduced models, which are activated by a pressure difference when the user inhales from the e-cigarette, avoiding pressing a button to heat the device. Other interesting new e-cigarette-like devices provide a combined function with other electronic products such as a Bluetooth e-cigarette, which combines vaping with listening to music or calling friends and another device can be used both as e-cigarette and mobile phone. Smartphone applications were introduced that track the number of e-cigarette puffs taken, calculate cost savings and increased life expectancy, and have features such as auto-shut down and password protection safety. In line with this, Philip Morris International has filed a patent for an e-cigarette that is Wi-Fi connected, and thus would be able to connect to other devices. This device could potentially synchronize to a smartphone application that is intended to help people quit smoking, and carefully track their progress. A similar product is the Vaporcade Jupiter, a "cellular vaporizer," combining a smartphone with an e-cigarette. This allows the user to monitor the e-cigarette use, the e-liquid remaining, and the flavor used. == Device generations ==

As the e-cigarette industry continues to evolve, new products are quickly developed and brought to market. The early devices looked like a traditional cigarette, often including a small light on the tip that lit when the user puffed. Since e-cigarettes are not regulated in many countries, the device designs can change often. There is wide differences in the quality of e-cigarettes, such as the airflow rate, aerosol production, and leaking of e-liquid cartridges. First-generation First-generation e-cigarettes started off as patents in periods of 1927–1936 and 1963–1998, but becoming commercially mainstream in 2003. They tend to look like tobacco cigarettes and so are called "cigalikes". They may be a single unit comprising a battery, coil and filling saturated with e-liquid in a single tube to be used and discarded after the battery or e-liquid is depleted. The cartomizer cartridge can be separated from the battery so the battery can be charged and the empty cartomizer replaced when the e-liquid runs out. Charging is commonly accomplished with a USB charger that attaches to the battery. Some manufacturers also have a cigarette pack-shaped portable charging case (PCC), which contains a larger battery capable of recharging the individual e-cigarette batteries. Reusable devices can come in a kit that contains a battery, a charger, and at least one cartridge. Second-generation Second generation devices started in 2013, and tend to be used by people with more experience. Second-generation e-cigarettes commonly use a tank or a "clearomizer". Second generation e-cigarettes may have lower voltages, around 3.7 V. Third-generation The third-generation started in 2013, it included mechanical mods and variable voltage devices. Battery sections are commonly called "mods," referencing their past when user modification was common. A larger "box mod" can hold bigger and sometimes multiple batteries. Common battery sizes used are 18350, 18490, 18500 and 18650. The battery is often removable, The power section may include additional options such as screen readout, support for a wide range of internal batteries, and compatibility with different types of atomizers. The larger battery sections used also allow larger tanks to be attached that can hold more e-liquid. Fourth-generation e-cigarettes can be made from stainless steel and pyrex glass, and contain very little plastics. Included in the fourth-generation are sub ohm tanks and temperature control devices. Usually used by experienced e-cigarettes users. == Atomizer and tank ==

)|alt=Inside view of an e-cigarette atomizer with the coil (heating element). An atomizer consists of a small heating element that vaporizes e-liquid and a wicking material that draws liquid onto the coil. Along with a battery and e-liquid the atomizer is the main component of every personal vaporizer. The electrical resistance of the coil, the voltage output of the device, the airflow of the atomizer and the efficiency of the wick all affect the vapor coming from the atomizer. They also affect the vapor quantity or volume yielded. Wicking materials vary from one atomizer to another. Cartomizers A "cartomizer" (a portmanteau of cartridge and atomizer.) or "carto" consists of an atomizer surrounded by a liquid-soaked poly-foam that acts as an e-liquid holder. When used in a tank, the cartomizer is inserted in a plastic, glass or metal tube and holes or slots have to be punched on the sides of the cartomizer so liquid can reach the coil. It contained the wicking material, an e-liquid chamber, and an atomizer coil within a single clear component. There are different wicking systems used inside clearomizers. Clearomizers are made with adjustable air flow control. Tanks can be plastic or borosilicate glass. Rebuildable atomizers A rebuildable atomizer (RBA) is an atomizer that allows the user to assemble or "build" the wick and coil themselves instead of replacing them with off-the-shelf atomizer "heads". They also allow the user to build atomizers at any desired electrical resistance. Rebuildable tank atomizers RTAs have a tank to hold liquid that is absorbed by the wick. They can use ceramic wicks, stainless steel mesh or rope for wicking material. These tanks have rebuildable or RBA kits. Rebuildable dripping atomizers RDAs are atomizers where the e-liquid is dripped directly onto the coil and wick. The common nicotine strength of e-liquids used in RDA's is 3 mg and 6 mg. They typically consist only of an atomizer "building deck", commonly with three posts with holes drilled in them, which can accept one or more coils. Pod mods Pod mods heat up a liquid containing nicotine, flavors, and other ingredients that creates an aerosol. small, and reusable. A pod mod does not require much of a learning curve. and there are many kinds of pod mods. Pod mods come in varying colors and flavors. Many devices rely on replaceable liquid pods that may contain propylene glycol, glycerin, benzoic acid, nicotine, and artificial flavors. Some pod mods can be refillable, with flavors such as cotton candy, donut cream, and gummy bear. Because pod mods are small and generate less aerosol, it makes it easy to hide them. Later-generation pod mods are small like a Sharpie pen. One nicotine pod, in terms of nicotine, is roughly equivalent to one pack of regular cigarettes. The labels on products state pods contain 59 mg/mL of nicotine, but the levels can be considerably greater such as 75 mg/mL of nicotine. In June 2015, Juul introduced a pod mod device. British American Tobacco told to The Verge in 2018 that "They've been incorporated in our Vuse e-liquid in the US since 2012." Research on nicotine salts is limited. Benzoic acid is the most used acid to create a nicotine salt. Nicotine salts are thought to amplify the level and rate of nicotine delivery to the user. Nicotine salts are less harsh and less bitter, and as a consequence e-liquids that contain nicotine salts are more tolerable even with high nicotine concentrations. Traditional cigarettes provide high levels of nicotine, but with the bad taste of smoking. Pod mods, however, can provide high levels of nicotine without the negative smoking experience. == Power ==

Variable power and voltage devices Variable devices are variable wattage, variable voltage or both. Recent devices can go up to 8 V. To adjust the settings, the user presses buttons or rotates a dial to turn the power up or down. The power source is the biggest component of an e-cigarette, which is frequently a rechargeable lithium-ion battery. The resistance changes are different for different types of wires, and must have a high temperature coefficient of resistance. Nickel, titanium, NiFe alloys, and certain grades of stainless steel are common materials used for wire in temperature control. The Evolv's DNA40 and YiHi's SX350J are control boards used in temperature control devices. Temperature control can stop dry wicks from burning, or e-liquid overheating. The term "mod" was originally used instead of "modification". Users would modify existing hardwares to get better performance, and as an alternative to the e-cigarettes that looked like traditional cigarettes. Users would also modify other unrelated items like flashlights as battery compartments to power atomizers. The word mod is often used to describe most personal vaporizers. Mechanical PVs have no power regulation and are unprotected. Because of this ensuring that the battery does not over-discharge and that the resistance of the atomizer requires electric current within the safety limits of the battery is the responsibility of the user. == E-cigarette liquid (e-liquid) ==

E-cigarette liquid, E-Cig liquid, vaping juice, e-juice, e-fluid is the mixture used in vapor products including e-cigarettes. Propylene glycol and glycerin typically comprise 95% , with the remaining 5% combining flavorings, nicotine, and other additives. Flavorings may contain menthol, sugars, esters, and pyrazines. Caffeinated e-liquids typically contain considerably less caffeine than dietary products. E-liquids are available with vitamins or cannabis flavors. More than 90% of e-liquids contain nicotine. Some are unflavored. E-liquids may contain THC or other cannabinoids. Some e-liquids contain a little alcohol. Nicotine levels vary. A user survey reported that 97% of respondents used nicotine e-liquids. A 2016 study reported that measurable amounts of arsenic, nickel and other metals were present in some e-liquids. Over 80 chemicals, including formaldehyde and metallic nanoparticles were reported in e-liquids (2019). E-liquid can contain toxicants and impurities. A 2013 study reported as high as five times the permitted levels of impurities. TSNAs present in tobacco smoke were reported in trace amounts. A 2013 review of other e-liquids did not detect diethylene glycol. The majority of the e-liquids analyzed contained NNN from 0.34 to 60.08 μg/L and NNK from 0.22 to 9.84 μg/L. E-liquids often contain unknown and/or undisclosed substances. Poor quality control may allow nicotine and TSNAs to be present in e-liquids labelled 'no nicotine'. A 2015 study reported hydrocarbons, terpenic compounds and aldehydes, particularly formaldehyde and acrolein in some e-liquids. A 2014 study reported that e-liquids from a specific manufacturer contained greater amounts of ethylene glycol than glycerin or propylene glycol, possibly the result of improper manufacturing methods. A 2015 study reported finding solvents such as 1,3-butadiene, cyclohexane, and acetone in e-liquids. Contents The e-liquid is sold in bottles, pre-filled disposable cartridges, or as a kit for consumers to make their own e-liquids. E-liquids are made with various tobacco, fruit, and other flavors, Some flavors are created to resemble the flavors used in traditional cigarettes such as tobacco and menthol-tobacco. Adults in general also preferred sweet flavors (though smokers like tobacco flavor the most) and disliked flavors that elicit bitterness or harshness. In surveys of regular e-cigarette users, the most popular e-liquids had a nicotine content of 18 mg/ml, and the preferred flavors were largely tobacco, mint and fruit. The most favorite flavors among regular e-cigarette users reported in a 2017 UK survey were fruit, tobacco, and menthol/mint. The survey also found 2.6% regular e-cigarette users used no flavors. A 2013 study examined 33 countries and found that only 1% of the adult smokers exclusively used non-nicotine e-cigarettes. E-liquids are frequently sold in dropper bottles. One cartridge may typically last as long as one pack of cigarettes. A refill bottle can contain up to 100 mg/ml of nicotine, which is meant to be diluted before use. Some users, probably due to financial reasons and the willingness to experiment, are opting to make homemade e-liquids. A small percentage of liquids without flavoring is also sold. The flavorings may be natural or artificial. About 8,000 flavors existed in 2014. More than 15,500 flavors existed in 2018. A user does not normally consume a whole cartridge in a single session. Standards E-liquid manufacturing requirements under the US Food and Drug Administration (FDA) rules include report user fee information, pay user fees, register their establishment and submit list of products, including labeling and advertisements, submit health documents, submit ingredient listing, include required warning statements on packages and advertisements, submit quantities of harmful and potentially harmful constituents, and submit a modified risk tobacco product application. AEMSA has published a comprehensive list standards and best known methods, which are openly available for use by any manufacturer of e-Liquids. AEMSA guidelines recommend that the nicotine levels in e-liquids be within the amount of ±10% from the levels stated on the label. Regulation Effective August 8, 2016, under the FDA rules, a company that mixes or prepares e-liquids is regulated as a tobacco product manufacturer. Companies who import or try to sell for import into the US must conform to the Federal Food, Drug, and Cosmetic Act. The 2016 FDA ruling did not incorporate regulation concerning flavoring of e-cigarettes. Industry standards have been created and published by the American E-liquid Manufacturing Standards Association (AEMSA). The FDA has sought to regulate e-liquid in 2014 through use of the Family Smoking Prevention and Tobacco Control Act, passed into law in June 2009. In April 2014, the FDA issued its "Deeming" proposals for public comment, which would cover e-liquids manufacturing. Manufacturers of e-liquid in the UK are required to inform the Government regarding the content in each liquid. The EU Tobacco Products Directive requires e-liquids to be tested 6 months before they are sold. The Tobacco Products Directive in the EU limits the sale of e-liquid. Refill liquids in the EU with more than 20 mg/ml of nicotine may be sold with prior authorization from the pharmaceutical regulation. Nicotine yield Smoking a traditional cigarette yields between 0.5 and 1.5 mg of nicotine, but the nicotine content of the cigarette is only weakly correlated with the levels of nicotine in the smoker's bloodstream. The amount of nicotine in the e-cigarette aerosol varies widely either from puff-to-puff or among devices of the same company. E-liquids contain nicotine in a variety of different strengths, from no nicotine to 36 mg/ml. On average a regular cigarette contains 6–28 mg of nicotine or the user will inhale about 1.1 to 1.8 mg of nicotine if just a portion is used. On average an e-cigarette contains 0.5–15.4 mg of nicotine per 15 puffs. In practice, the nicotine concentration in an e-liquid is not a reliable guide to the amount of nicotine that reaches the bloodstream. == Notes ==