I've salvaged the thin fluorescent tube from the scanner section of a Cannon scanner/printer/copier. As the power supply had a number of unmarked voltages I guessed at 12V for the tube electronics but it only lights up 3/4 of the length, should I risk a higher voltage?
I wanted to see if I could use it as a low power light for a hallway after lights out.
AJH
The message from AJH contains these words:
Are you sure the scanner was actually working?
OK but I was trying to recycle some bits rather than dumping them, still looking at two stepper motors...
No but the previous owner junked it because of a (well known) print head fault, so I guessed it would be OK.
AJH
I assume you can't resurrect it enough to measure the voltage?
Other causes of this might be tube too close to metalwork so current leaks out capacitively, or conductor to far-end electrode broken.
You will probably find it's a rather revolting blue-white colour for use in the home.
JKL is a well-known manufacturer of the 2mm diameter fluorescent tubes and inverters, and you might get some useful information from their website:
When I touch the tube the illuminated length changes as my finger moves over it.
Although quite bright to look at I'm a bit disappointed in the amount of illumination it provides, currently I leave a small 11W cfl on, with a sound activated switch, so I can see my way down the stairs in an emergency but it's become a bit erratic.
AJH
I pulled the psu out but lost which of the outputs ran the exciting circuit for the tube, I'll have to dig out my dmm and check the psu outputs.
AJH
11W is only 3 quid or so per year, 8 hours a day.
I'm at the moment installing - along with other work - 10 1W 'warm white' LEDs as emergency lighting.
These go across a rough 5V bus, going round the house, powered from a large battery, and are on 8 hours/day or so.
This is not a whole lot of light, but it's completely adequate for not walking into things if you haven't come from light outside. And if you have, then more light'll be coming in anyway.
Unfortunately, in some cases, the PSU may not output proper voltages unless loaded. You may get lucky though.
Why not hook it up to 14v and see if it lights a bit further along.
I would not touch the tube while on, these are typically run off high voltage high frequency and use external foil electrodes. Very long life but fingers off.
Alternatively get a 3w cfl.
NT
I shall give it a try but 12V was convenient (gel cell car battery booster to hand)
Thanks for the warning.
AJH
or use existing supply but put it thru 2 diodes to drop 2v, and see if its worse.
NT
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