Mobile phone commercially available handheld mobile phone. From 1983 to 2014, worldwide mobile phone subscriptions grew to over seven billion—enough to provide one for every person on Earth. In first quarter of 2016, the top smartphone developers worldwide were Samsung, Apple, and Huawei, with smartphone sales represented 78 percent of total mobile phone sales. For feature phones (or "dumbphones") , the largest were Samsung, Nokia, and Alcatel. A handheld mobile radio telephone service was envisioned in the early stages of radio engineering. In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone".
Mobile phone overuse Microwave auditory effect which was discovered in 1962. Studies show that users often associate using a mobile phone with headaches, impaired memory and concentration, fatigue, dizziness and disturbed sleep. There are also concerns that some people may develop electrosensitivity from excessive exposure to electromagnetic fields, although these symptoms may be primarily psychological in origin due to the nocebo effect. Using a cell phone before bed can cause insomnia, according to a study by scientists from the Karolinska Institute and Uppsala University in Sweden and from Wayne State University in Michigan. The study showed that this is due to the radiation