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A mechanically powered flashlight (UK: mechanically powered torch) is a flashlight that is powered by electricity generated by the muscle power of the user, so it does not need replacement of batteries, or recharging from an electrical source. There are several types which use different operating mechanisms. They use different motions to generate the required power; such as squeezing a handle, winding a crank, or shaking the flashlight itself. These flashlights can also be distinguished by the technique used to store the energy: a spring, [1] a flywheel, a battery or a capacitor.
Since they are always ready for use, mechanically powered flashlights are often kept as emergency lights in case of power outages or other emergencies. They are also kept at vacation homes, cabins, and other remote locations because they are not limited by battery shelf life like ordinary flashlights. They are considered a green technology, because the disposable batteries used by ordinary flashlights are wasteful in terms of resources used for the amount of energy produced, and also contain heavy metals and toxic chemicals which end up in the environment.
A dyno torch, dynamo torch, or squeeze flashlight is a flashlight or pocket torch which generates energy via a flywheel. The user repeatedly squeezes a handle to spin a flywheel inside the flashlight, attached to a small generator/dynamo, supplying electric current to an incandescent bulb or light-emitting diode. The flashlight must be pumped continuously during use, with the flywheel turning the generator between squeezes to keep the light going continuously. Because electrical power is produced only when the handle is squeezed, a switch is unnecessary. Dyno lights were issued to German Wehrmacht soldiers during World War II. They were popular in Europe during the war because the electrical power supply to homes was unreliable. In addition to "squeeze flashlight", American soldiers often referred to such lights as "squeezy flashlight" or even "squeegee flashlight".[ citation needed ]
A version using a pull-cord was used in World War I. [2]
The photo shows the internal mechanism: the L-shaped handle has a gear rack, which spins the white step-up gear, which in turn spins the flywheel on which is mounted both a centrifugal clutch (to allow freewheeling after the lever stops its travel and then returns) and a dark grey magnet, seen on the lower left. The magnet induces an electric current as it spins around the red copper winding, seen on the lower right. The current from the copper winding flows through the filament of an incandescent light bulb (not shown), giving off light. An L-shaped spring returns the handle to its original position after each engagement.
The linear induction, Faraday flashlight, or "shake flashlight" is another type of mechanically powered flashlight. It has been sold in the US beginning with direct marketing campaigns in 2002.
This design contains a linear electrical generator which charges a supercapacitor which functions similarly to a rechargeable battery when the flashlight is shaken lengthwise. The battery or capacitor powers a white LED lamp. The linear generator consists of a sliding rare-earth magnet which moves back and forth through the center of a solenoid (a coil of copper wire) when it is shaken. A current is induced in the loops of wire by Faraday's law of induction each time the magnet slides through, which charges the capacitor through a rectifier and other circuitry.
The best designs use a supercapacitor instead of a rechargeable battery, since these have a longer working life than a battery. This, along with the long-life light-emitting diode which does not burn out like an incandescent bulb, give the flashlight a long lifetime, making it a useful emergency light. A disadvantage of many current models is that the supercapacitor cannot store much energy in comparison to a lithium-ion cell, limiting the operating time per charge. In most designs, vigorously shaking the light for about 30 seconds may provide up to 5 minutes of light, though the advertised time omits the reduced output of the LED after 2 or 3 minutes. Shaking the unit for 10 to 15 seconds every 2 or 3 minutes as necessary permits the device to be used continuously. It is often viewed as a toy, or an emergency backup for other flashlights. [3]
Fraudulent counterfeit versions of these flashlights have been sold, most of which incorporate hidden coin-sized non-rechargeable lithium batteries. The expensive supercapacitor is omitted from the internal components. In some of these fake designs, the "magnet" is not a magnet or the coil is not connected, and no electricity is generated when the device is shaken. These fraudulent flashlights eventually become useless, since their internal batteries cannot be recharged or replaced, and the case is often permanently glued shut. [3] [4]
Another common type is the windup or crank-powered flashlight, with the light powered by a battery which is recharged by a generator turned by a hand crank on the flashlight. One minute of cranking typically provides about 30 to 60 minutes of light. It has the advantage that it doesn't have to be pumped continually during use like the dyno torch or some shake flashlights. However it may be less reliable as an emergency light, because the rechargeable battery it contains eventually wears out. The lithium-ion cells used are typically rated for around 500 charges.
In an alternative "Clockwork Torch" design, produced by Freeplay Energy, the energy is mechanically stored in a flat spiral wound mainspring, rather than a battery. The owner winds the spring up by turning the crank. Then when the light is turned on (by releasing a mechanical brake), the spring unwinds, turning a generator to provide power to run the light. The purpose of this design, originally invented for use in the developing world, was to improve its reliability and useful lifetime by avoiding or reducing reliance on a battery. By 2012 the original design was no longer made, but updated smaller hand-cranked models using LEDs were still available.
Some mechanically powered flashlights include additional functions and features beyond just a source of light. Models sold as emergency lights have additional functions intended to be used in emergencies, such as flashing red or yellow lights for roadside emergencies, sirens, and radios such as AM/FM, weather, or shortwave radios. They may also include alternative means of charging the battery, such as an AC adaptor, solar cells, or cords that plug into a cigarette lighter socket in a car.
Crank powered flashlights often have radios and other features. One popular feature is a 5-volt USB charging port for recharging cell phones when an outlet is not available. The quality and long-term reliability of these devices vary over a wide range, from high-reliability mil-spec emergency equipment down to one-time-use non-repairable disposables.
The first mechanically powered portable illumination was the "steel mill", used in coal mining during the 1800s. These lamps consisted of a steel disk, rotated at high speed by a crank mechanism. Pressing a flint against the disk produced a shower of sparks and dim illumination. [5] These mills were only used in coal mines, where a risk of explosive firedamp gas made candle lighting unsafe. Caution was required to observe the sparks, so as not to generate very hot sparks that could ignite firedamp. [6] These mills were troublesome to use and were often worked by a boy, whose only task was to provide light for a group of miners. One of the first of these mills was the 18th century Spedding mill, [7] the Spedding family having a long association as the agents for the Lowther family of Westmorland and the Whitehaven collieries. [5]
Steel mills went out of favor after the introduction of the much less cumbersome Davy and Geordie lamps from 1815. The mill idea was revived in 1946, based on the developed technology of cigarette lighters and ferrocerium flints. A spring-wound lamp with eight flints was suggested for emergency signalling at sea. [8]
An uninterruptible power supply (UPS) or uninterruptible power source is a type of continual power system that provides automated backup electric power to a load when the input power source or mains power fails. A UPS differs from a traditional auxiliary/emergency power system or standby generator in that it will provide near-instantaneous protection from input power interruptions by switching to energy stored in battery packs, supercapacitors or flywheels. The on-battery run-times of most UPSs are relatively short but sufficient to "buy time" for initiating a standby power source or properly shutting down the protected equipment. Almost all UPSs also contain integrated surge protection to shield the output appliances from voltage spikes.
In electricity generation, a generator is a device that converts motion-based power or fuel-based power into electric power for use in an external circuit. Sources of mechanical energy include steam turbines, gas turbines, water turbines, internal combustion engines, wind turbines and even hand cranks. The first electromagnetic generator, the Faraday disk, was invented in 1831 by British scientist Michael Faraday. Generators provide nearly all the power for electrical grids.
A starter is a device used to rotate (crank) an internal-combustion engine so as to initiate the engine's operation under its own power. Starters can be electric, pneumatic, or hydraulic. The starter can also be another internal-combustion engine in the case, for instance, of very large engines, or diesel engines in agricultural or excavation applications.
An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In principle, any AC electrical generator can be called an alternator, but usually, the term refers to small rotating machines driven by automotive and other internal combustion engines.
A flashlight or electric torch, usually shortened to torch, is a portable hand-held electric lamp. Formerly, the light source typically was a miniature incandescent light bulb, but these have been displaced by light-emitting diodes (LEDs) since the early 2000s. A typical flashlight consists of the light source mounted in a reflector, a transparent cover to protect the light source and reflector, a battery, and a switch, all enclosed in a case.
Bicycle lighting is illumination attached to bicycles whose purpose above all is, along with reflectors, to improve the visibility of the bicycle and its rider to other road users under circumstances of poor ambient illumination. A secondary purpose is to illuminate reflective materials such as cat's eyes and traffic signs. A third purpose may be to illuminate the roadway so that the rider can see the way ahead. Serving the latter purposes require much more luminous flux and thus more power.
A motor–generator is a device for converting electrical power to another form. Motor–generator sets are used to convert frequency, voltage, or phase of power. They may also be used to isolate electrical loads from the electrical power supply line. Large motor–generators were widely used to convert industrial amounts of power while smaller motor–generators were used to convert battery power to higher DC voltages.
An emergency light is a battery-backed lighting device that switches on automatically when a building experiences a power outage.
A light fixture, light fitting, or luminaire is an electrical lighting device containing one or more light sources, such as lamps, and all the accessory components required for its operation to provide illumination to the environment. All light fixtures have a fixture body and one or more lamps. The lamps may be in sockets for easy replacement—or, in the case of some LED fixtures, hard-wired in place.
A linear alternator is essentially a linear motor used as an electrical generator.
Eveready Industries India Ltd. (EIIL) is an Indian company that manufactures and markets batteries and lighting products. The Eveready brand has been present in India since 1905. It also manufactures photogravure plates, castings, carbon electrodes and related products.
A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundation upon which many other later electric-power conversion devices were based, including the electric motor, the alternating-current alternator, and the rotary converter.
Freeplay Energy Ltd, , is a manufacturer and distributor of portable electrical or electronic products such as radios and lights, generally powered by hand cranked generators that charge rechargeable batteries. The company is based in London, UK. The company focuses on creating and developing the international market for self-sufficient energy products, and states that such a focus will help promote education and access to important information throughout the developing world. The company has expanded its market to include outdoor leisure and emergency preparedness markets, seeing the clear demand for self-powered products in such off-grid environments.
Human power is the rate of work or energy that is produced from the human body. It can also refer to the power of a human. Power comes primarily from muscles, but body heat is also used to do work like warming shelters, food, or other humans.
A solar charger is a charger that employs solar energy to supply electricity to devices or batteries. They are generally portable.
A headlamp, headlight, or head torch (UK) is a light source affixed to the head typically for outdoor activities at night or in dark conditions such as caving, orienteering, hiking, skiing, backpacking, camping, mountaineering or mountain biking. Headlamps may also be used in adventure races. Headlamps are often used by workers in underground mining, search and rescue, surgeons, and by other workers who need hands-free directed lighting.
A magneto is an electrical generator that uses permanent magnets to produce periodic pulses of alternating current. Unlike a dynamo, a magneto does not contain a commutator to produce direct current. It is categorized as a form of alternator, although it is usually considered distinct from most other alternators, which use field coils rather than permanent magnets.
Solar powered flashlights or solar powered torches are flashlights powered by solar energy stored in rechargeable batteries. Most of these flashlights use light-emitting diodes lamps since they have lower energy consumption compared to incandescent light bulbs.
A supercapacitor (SC), also called an ultracapacitor, is a high-capacity capacitor, with a capacitance value much higher than solid-state capacitors but with lower voltage limits. It bridges the gap between electrolytic capacitors and rechargeable batteries. It typically stores 10 to 100 times more energy per unit volume or mass than electrolytic capacitors, can accept and deliver charge much faster than batteries, and tolerates many more charge and discharge cycles than rechargeable batteries.
An alternator is a type of electric generator used in modern automobiles to charge the battery and to power the electrical system when its engine is running.