How to Check a Light Bulb with a Multimeter: 1 Minute to Test Your Light Bulb like a Pro

To check if a light bulb is functioning properly using a multimeter, you'll need to test for continuity or resistance across the bulb’s terminals. Start by ensuring the light bulb is removed from any fixture and is completely cool. Set your multimeter to the “continuity” or lowest “ohms (Ω)” setting. Touch one probe to the metal base and the other probe to the bottom contact point of the bulb. If the bulb is good, you’ll hear a beep (on continuity mode) or read a resistance typically between 1 to 200 ohms for most incandescent bulbs. If you see no reading (an open circuit), the filament is broken and the bulb is bad. For LED or CFL bulbs, visual inspection is often better, as their internal circuitry may not show continuity, but you can still check for obvious circuit breaks or opens.

Tips 1:

As a designer, I often find that maintaining consistent lighting—in both performance and design aesthetic—is critical for any interior space. Whether you’re troubleshooting a statement fixture or the general AI Interior Design of an entire room, learning to check bulbs yourself ensures your lighting design always shines as intended.

FAQ

Q: Can you check LED bulbs with a multimeter?

A: LED bulbs often have complex electronics inside, so a basic continuity test might not be conclusive. Visual inspection for damage is often more effective.

Q: What resistance should a working incandescent bulb have?

A: Most working incandescent bulbs will show a resistance between 1 and 200 ohms, depending on wattage and bulb size.

Q: Can a multimeter damage a light bulb during testing?

A: No, multimeter voltage is too low to damage bulbs. Just be sure the bulb is not connected to power.

Q: Is it safe to test light bulbs with a multimeter?

A: Yes, as long as the bulb is removed from live fixtures and completely cool before testing.

Q: Why won't my multimeter beep or show continuity for a CFL bulb?

A: CFL bulbs have internal circuitry that may prevent a continuity check from working. Use visual inspection or test the bulb in a working fixture for best results.