← TAKE IT APART

The flashlight

Turn it on. Then take it apart.

35%

This switch turns the model on. The real one is two springs and a loop — wire it on the bench.

The pieces

  1. the tube The cardboard tube that holds everything else in a straight line, bulb at one end, battery at the other.
  2. the end cap A turned wood disc that plugs the back of the tube shut and holds the battery in from behind.
  3. the bulb The bulb, pulling about 560 mA the instant it lights and settling to about 63 mA once the filament heats up. Build the same lamp at Light the lamp. Build it on the bench →
  4. the switch The slide switch that makes or breaks the 9 V line to the bulb. Build the two-switch version at Series switches. Build it on the bench →
  5. the battery A 9 V battery, wedged against the end cap. Build the circuit that uses it at Ohm's law. Build it on the bench →