Follow the explanation
Back to the model ↑How the parts work together
Follow the only conducting route
Start at the bottom contact, then follow its lead through the sealed stem, along the coil, and down the other lead to the shell. The support ends in glass and does not bypass the filament. Orbit beneath the base to find the terminal insulation.
Make the filament hotter
Raise temperature from 1600 K toward 3000 K. The ideal Planck curve grows on the same vertical scale at every setting. The filament color is only a display cue; the graph is the mathematical comparison. Play sweeps temperature, not actual heating time.
Find the infrared peak
At 3000 K the ideal peak is still about 966 nm, outside the marked 380–780 nm visible interval. Visible emission increases without becoming the whole output. Close the cutaway to restore the complete glass envelope.
The main parts
- Coiled tungsten filament
- The continuous coil joins both lead wires. Its fine wire is exaggerated for inspection. The glow changes with the chosen temperature; its RGB appearance is illustrative, not a colorimetric measurement.
- Two lead-in wires
- One lead joins the bottom contact to the left filament end; the other joins the right end to the screw shell. They stay separate through the glass stem. No supply is shown, so this is a construction view, not a live circuit simulation.
- Sealed glass stem
- The flare joins the envelope at its neck. The pressed glass seals around the two wires; a closed exhaust tip represents where the lamp was evacuated and filled. Glass also anchors the support.
- Dead-ended support
- A support wire runs from insulating glass to one point of the filament. It supports the coil without providing a second conducting route between the terminals.
- Glass envelope
- The envelope separates the filament from room air. A real incandescent lamp may contain inert fill gas, which is not drawn. The cutaway deliberately removes the front half to reveal the assembly.
- Threaded metal shell
- The screw shell is one electrical terminal as well as a mechanical connection. Follow its inner lead toward the filament. The continuous thread is illustrative, not a verified socket specification.
- Insulating glass at the base
- The dark glass separates the shell from the central bottom contact. Rotate beneath the bulb to inspect the visible gap between those two metal terminals.
- Bottom contact
- This separate metal contact is the other terminal. Its lead rises through the sealed stem to one end of the filament; it does not touch the screw shell.