Dynamo flashlight
A dynamo flashlight is an electric light that is mechanically powered by a small electrical generator . This enables the lamp to be operated in a period of a few seconds, or up to a few minutes for constructions with a small flywheel , capacitor or accumulator integrated in the lamp as a temporary energy store.
Conventional flashlights are powered by batteries or accumulators.
The first mechanical dynamo flashlights date from the beginning of the 20th century, when early batteries like the Daniell element could not be operated in any position.
function
There are various methods for driving the generator. Common methods are a lever built into the lamp, which must be depressed periodically, or a small hand crank . There are also designs in which a flywheel is set in rotation by pulling out a thread, which drives the generator for a short period of time.
In addition to small incandescent lamps , LEDs and fluorescent lamps are also used as light sources . The performance is in the order of 1 W .
The electricity generated by the generator is stored in a Li-Ion battery (see Figure 3 ) or, in the case of more expensive models, in a super capacitor . This allows the flashlight to glow for several minutes if the charging time is long enough without the user having to continuously drive the generator. LEDs are used as the light source due to their low power consumption. A button can often be used to set different flashing and parking light modes.
For dynamo flashlights without energy storage, no switch is necessary due to the function .
Areas of application
Since mechanical dynamo flashlights, driven purely by muscle power, are not dependent on electrical energy storage devices such as batteries or rechargeable batteries for the availability and functionality, they are used, among other things, as emergency lights. In contrast to battery-operated flashlights, whose energy stores continuously lose power due to their self-discharge even when switched off, dynamo-operated flashlights have practically no time-limited shelf life.
Due to their simple structure, they are also used in various forms as objects for demonstration and experimentation in physical education in schools.
Dynamo flashlights are also used where the availability of commercially available electric batteries is not guaranteed, such as in rural regions of Africa .
literature
- Jörg Willer: Didactics of Physics Lessons . 1st edition. Harri Deutsch, 2003, ISBN 978-3-8171-1693-5 .
Individual evidence
- ↑ German pocket flashlight contains own dynamo . In: Popular Mechanics Co. (Ed.): Popular Mechanics . 32, No. 4, Chicago, December 1919, p. 804. Retrieved May 16, 2013.
