Base
VisibleSteel plate or cast zinc inside a polymer or aluminium shell
The base is deliberately heavy. Its mass has to counterbalance a fully extended arm, so the cheapest dense material that fits is used.
What is a desk lamp made of?
A modern LED desk lamp is a heatsink with a light source attached. Almost every design decision — the arm, the base, the housing material — is downstream of getting heat away from the diodes and keeping the lamp from tipping over.
What a desk lamp is made of, part by part
6 parts — 4 you can see, 2 you can’t without opening it.
Arm and joints
VisibleSteel tube or extruded aluminium, with steel springs and nylon washers
In a sprung arm the springs balance the head at every angle. Nylon washers set the friction so joints hold position without being stiff to move.
LED board
HiddenAluminium-core PCB with surface-mounted LEDs and a phosphor coating
An aluminium core conducts heat out of the diodes into the housing. LEDs emit blue light; the phosphor layer converts part of it, which is what sets the colour temperature.
Driver
HiddenFR-4 board with electrolytic capacitors, an inductor, and a switching IC
It converts mains AC to a constant current. The electrolytic capacitors are the shortest-lived component in the whole lamp and usually decide its lifespan.
Diffuser
VisibleFrosted polycarbonate or acrylic
It scatters the point sources into an even strip. Polycarbonate tolerates the heat close to the LEDs better; acrylic stays clearer over time but yellows if run hot.
Housing
VisibleExtruded aluminium, or ABS on cheaper lamps
Aluminium doubles as the heatsink. An ABS housing means the heat has nowhere to go, which is why cheap LED lamps dim years before their rated hours.
What the materials list doesn’t tell you
"50,000 hour" LED ratings describe the diodes in isolation. In a real lamp the driver's capacitors, and the heat the housing fails to remove, decide the actual life — usually a fraction of the rated figure.
Can it be repaired?
Most LED lamps are sealed or glued, and the LED board is often soldered directly to the driver. Where a lamp uses a replaceable bulb it's far more repairable, which is a genuine argument for the older format.
Common questions
- Why has my LED desk lamp got dimmer over time?
- Why is my desk lamp base so heavy?
- Does colour temperature affect eye strain?
Yours won’t be exactly this one
This page describes the category. Exploded reads the specific object in front of you — photograph your desk lamp and get a breakdown of its parts, with every guess labelled as a guess, then explore what could be built differently.
Analyze your desk lamp