what type of device is a bicycle dynamo
magnetos
title: Bottle dynamo text: Bottle dynamo A bottle dynamo or sidewall dynamo is a small electrical generator for bicycles employed to power a bicycle's lights. The traditional bottle dynamo (pictured) is not actually a dynamo, which creates DC power, but a low-power magneto that generates AC. Newer models can include a rectifier to create DC output to charge batteries for electronic devices including cellphones or GPS receivers. Named after their resemblance to bottles, these generators are also called "sidewall dynamos" because they operate using a roller placed on the sidewall of a bicycle tire. When the bicycle is in motion and the dynamo roller title: Bottle dynamo text: is engaged, electricity is generated as the tire spins the roller. Two other dynamo systems used on bicycles are hub dynamos and bottom bracket dynamos. Bottle dynamo A bottle dynamo or sidewall dynamo is a small electrical generator for bicycles employed to power a bicycle's lights. The traditional bottle dynamo (pictured) is not actually a dynamo, which creates DC power, but a low-power magneto that generates AC. Newer models can include a rectifier to create DC output to charge batteries for electronic devices including cellphones or GPS receivers. Named after their resemblance to bottles, these generators are also called "sidewall title: Dynamo text: for electrical power. Dynamos were used in motor vehicles to generate electricity for battery charging. An early type was the third-brush dynamo. They have, again, been replaced by alternators. Dynamos still have some uses in low power applications, particularly where low voltage DC is required, since an alternator with a semiconductor rectifier can be inefficient in these applications. Hand cranked dynamos are used in clockwork radios, hand powered flashlights, mobile phone chargers, and other human powered equipment to recharge batteries. Dynamo A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators title: Bicycle text: include utility bicycles, mountain bicycles, racing bicycles, touring bicycles, hybrid bicycles, cruiser bicycles, and BMX bikes. Less common are tandems, low riders, tall bikes, fixed gear, folding models, amphibious bicycles, cargo bikes, recumbents and electric bicycles. Unicycles, tricycles and quadracycles are not strictly bicycles, as they have respectively one, three and four wheels, but are often referred to informally as "bikes" or "cycles". A bicycle stays upright while moving forward by being steered so as to keep its center of mass over the wheels. This steering is usually provided by the rider, but under certain conditions may be provided by title: Bicycle lighting text: and lighter weight compared with conventional batteries. More specifically, the 18650 battery, which has been popular with electric car manufacturers (for the same reasons) and are commonly found in laptops and flashlights. Dynamo systems require no batteries and may be permanently fitted to the bike. Bicycle dynamos are actually magnetos and produce alternating current. There are three main types: Other types of dynamos exist, but are less common. For example, there are dynamos that are attached to the fork and driven by the wheel's spokes. Dynamos are generally limited to about 3 W of output power, although the best 12