How A Flashlight Works


The Parts

Case-The housing, usually a tube, that holds the parts together

Switch-Component that controls the flow of electricity

Reflector-Plastic or metal piece that mounts around the lamp

Contacts-Thin metal springs or strips that complete the electrical circuit

Lamp-The light source, either a tungsten filament or a light emitting diode

Lens-Clear glass or plastic that protects and magnifies the lamp

Batteries-The source of power for the Lamp

How They Work Together

Pushing the switch to the “on” postion” allows the contacts to complete the circuit between the lamp and the batteries.  Once electricity flows from the batteries, the filament in the lamp, or the light emitting diode, begins to glow.

Battery placement is critical, since the electricity must flow from the positive terminal of the battery, through the lamp, to the negative terminal in order for the lamp to energized.

Once the filament or LED starts to glow, it produces a visible light that reflects off the reflector and away from the lens.

The lens focuses, and in some cases, magnifies the light, producing a steady beam.

Pressing the switch to the “off” position interrupts the flow of electricity and extinguishes the flashlight beam. is your source for Procell alkaline batteries from Duracell.
Your satisfaction is always guaranteed.

Harrison Bros. Inc.
Voice 877-863-6150
Fax     800-327-6651