MAMEWorld Forums - The Loony Bin - Re: Dayum, and I was worried this LED bulb might not be bright enough.

Not voltage, but current.

If one of the lights going out didn't cause the rest to go out, then that would imply that the bulbs were wired in parallel across the incoming mains to the fixture.

In that case, the amount of voltage to each bulb is the same, but the amount of current is divided up equally across each bulb.

Please note that all of the following numbers are largely made up, but it's to illustrate the point:

Incandescent bulbs are purely resistive loads, so with (let's say) 5 55W bulbs in parallel, each one takes 110V but had a 0.5A load on the circuit.

LED bulbs, by contrast, consume considerably less current. Not zero, but let's assume it's zero because it makes the math easier. Now you have 110V, and that same amount of current (2.5A) being distributed across four incandescent bulbs instead. Each bulb will now be dissipating almost 70 watts! It's no surprise that this would dramatically shorten the lifespan of the bulbs. Once the first of the remaining 4 incandescent bulbs burns out, that's over 90 watts being thrown off by the remaining 3, which accelerates the deterioration even further, so another blows, now there's nearly 140 watts split across the last two, and so on.

So yeah, if you have a single light fixture with multiple bulbs, replace all the bulbs at the same time.