Fluorescent Tube Life

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handy10

Senior Member
For a T12 fixture with magnetic ballast, there are three things that can cause the fixture to fail to give light: the bulb, the ballast, and the sockets. Are there measurements that can determine which of these is responsible for failure? I suppose visual inspection of the sockets is about the best one can do, but what of bulbs and ballasts?
 

John120/240

Senior Member
Location
Olathe, Kansas
Flourscent bulbs

Flourscent bulbs

To test the bulbs, use a bulb tester. It looks like a transistor radio with an antenna with 9v battery. Pull out antenna & touch the bulb & it will light up.
Someone will have the technical name for tester.
 

broadgage

Senior Member
Location
London, England
IME the testers refered to can give very misleading results, they apply a high voltage high frequency field to the outside of the lamp, or to one terminal.
This ionises the gas within and causes it to glow, that only proves that the bulb still contains the correct gas mixture, it does not prove that the filaments are continous or have retained the power to emit electrons.

The easiest way to test flourescent lamps is to insert them into a known working fixture.

The easiest way to test a ballast is to connect it to a known working lamp.
If you suspect that the ballast has a fault that destroys the lamps, then to avoid waste, use well used but proved functional lamps for the test.

A crude test of 2 wire switch-start ballasts is simply to connect them to the line via a fuse, and observe if any current is drawn.
Open circuit=no good
Short circuit=no good
Moderate current=probably OK
That only applies to 2 wire ballasts, those with more connections are best tested with a lamp.
 
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