Lighting, Light Fixtures, Ceiling and Exhaust Fans - dusk to dawn motion sensor

Hi all,

I want to use an outside motion detector with 120v landscape ficture to light up a flag pole. I found a sensor with a dusk to down hi/lo 4hr feature. This is perfect for my use. Question, will running the bulb in the lo position (20% power) reduce the life of the bulb? The bulb is a par20 halogen. Thanks Bob

Hi all,

I want to use an outside motion detector with 120v landscape ficture to light up a flag pole. I found a sensor with a dusk to down hi/lo 4hr feature. This is perfect for my use. Question, will running the bulb in the lo position (20% power) reduce the life of the bulb? The bulb is a par20 halogen. Thanks Bob

Running the bulb at 20% should make the lamp last nearly forever.

What you'll have to check though, is if the sensor is suitable for operating a halogen lamp. Some are, some aren't.

>Running the bulb at 20% should make the lamp last nearly forever.<
What is actually going on when the bulbs are dimmed, is the sensor just reducing the voltage?

Thanks bob

Dimmers have a device called a triac. It essentially turns off and on the flow of electricity many times a second.

> It essentially turns off and on the flow of electricity many times a second.<
You would think that would reduce the life of the bulb. The constant heating and cooling of the bulb wire.

Bob

The filiment runs much cooler because it is on less. Heat kills filiments. Even dimmed from 100% to 90% makes a bulb last significantly longer.