Hand Cranked Flashlight
About 2 min read
A hand cranked flashlight is a useful type of flashlight that can be used without worrying that the batteries are still good. This electric machine uses muscle power to turn an electric generator and create the current needed to light the bulbs.
The parts of the hand cranked flashlight are the crank, gears, electric generator, electronics, battery, and light-emitting diodes (LEDs).
Cranking the handle rotates the gears inside the flashlight, which then turn the generator rotor. This charges the battery and provides electricity to light the LEDs.
Questions you may have include:
- How is the flashlight an electric machine?
- What does the flashlight look like?
- How do the internal parts function?
This lesson will answer those questions.
Electric machine
A hand cranked flashlight turns muscle power into electrical power and then visible light. The crank turns gears that create a speed mechanical advantage and turn the generator at a fast rate.
The rotors of the generator convert motion into electrical energy that then charges a battery. The current then goes to the LEDs to create visible light.
Full view of flashlight
A hand cranked flashlight has a crank on its back side that folds up. There is a button switch on the top of the flashlight.
Flashlight
The flashlight has a crank on its back side that you can turn to generate the electricity required to charge the battery and light the bulbs, which are light-emitting diode (LED) bulbs. LED bulbs require much less electricity than standard bulbs, and they put out more light.
Flashlight crank handle
Inside of flashlight
Taking the flashlight apart allows you to see its parts.
Crank assembly removed
First, the crank assembly is removed, allowing you to see the inside electronics.
Crank assembly removed
Gears turn generator
You can take the electronics board out to view the gears. The crank turns one set of gears that increase the speed of the final gear that is attached to the generator.
Flashlight disassembled to show gears
Generator charges battery
The generator is made of permanent magnets and a wire rotor. It both charges the battery and lights the LEDs. With a charged battery, you do not need to turn the crank.
Generator charges the battery
Summary
The hand cranked flashlight is an electric machine that uses muscle power to turn an electric generator and create the current needed to light the LED bulbs.
Cranking the handle rotates the gears inside the flashlight, which then turn the generator rotor. This charges the battery and provides electricity to light the LEDs.
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Resources and references
Websites
Mechanically powered flashlight – Wikipedia
Electrical machine – Wikipedia
Electric machine – Wikipedia
Electromechanics – Wikipedia