Florescent bulb lights up on D batteries.

[gary350]

When I was in college we use to light up florescent bulbs with 6 or 8 D flash light batteries. I remember this worked good in summer in warm weather but not in winter if bulb was too cold. Also remove a hot bulb from a light fixture it was easy to light up with a few D batteries. Push and hold the switch down about 2 seconds then click switch on/off a few times fast bulb would light up. This was 50 years ago I must have forgotten something I can't make it work. I seem to recall filaments were about .4 amps each but don't remember filament voltage? 2 ft long florescent bulbs light up easier than 4 ft bulbs and 8 ft was harder.

 

[JonSea]

Doubtful. According to this reference, it takes at least 30 volts to maintain the light, and a hundred volts or more to start the tube.

 

[rjenkinsgb]

I think your drawing has the switch in the wrong wire - it should be in the link between the filaments.

That should at least produce a momentary flicker, though it would need quite a bit of voltage to be able to sustain light!

It is using the back EMF from the inductor to create a high voltage spike and "strike" the tube when the current path through filaments is broken.


I've never tried that - though I did run them off conventional xenon strobe tube circuits, using a wrap of wire near one end as the trigger terminal.
It's quite effective when the tube is cold, but at anything other than a very low flash rate they start to conduct continuously after a few seconds as they warm up.

 

[Nigel Goodwin]

I see Gary has been smoking dubious herbs again

At best that would light up the heaters, but no way could the tube strike.

 

[gary350]

I think your drawing has the switch in the wrong wire - it should be in the link between the filaments.

That should at least produce a momentary flicker, though it would need quite a bit of voltage to be able to sustain light!

It is using the back EMF from the inductor to create a high voltage spike and "strike" the tube when the current path through filaments is broken.


I've never tried that - though I did run them off conventional xenon strobe tube circuits, using a wrap of wire near one end as the trigger terminal.
It's quite effective when the tube is cold, but at anything other than a very low flash rate they start to conduct continuously after a few seconds as they warm up.

I think your right switch was in wrong place. 3 of us in high school electronic class experimented with this every day for a week or 2. We must have used more D batteries than I remember. I remember connecting batteries in parallel with each filament just to see what voltage was needed to make it glow orange color but I don't remember the filament voltage. Online circuit shows 230v on both filaments in series that would = 115vac on each filament, we never had that many D batteries. I wonder if a joule thief circuit will make this work.

 

[tvtech]

Getting old is hard to handle
I'm battling with it Sometimes I think I was Superman. Nope. I've forgotten probably most of what I was taught

So, I mostly don't post. I mean Off Topic is a safer place for me.

There I just wobble along and moan and groan and comment about the current situation here in South Africa.

 

[rjenkinsgb]

I remember connecting batteries in parallel with each filament just to see what voltage was needed to make it glow orange color but I don't remember the filament voltage. Online circuit shows 230v on both filaments in series that would = 115vac on each filament

Remember that in a basic fluorescent fitting there is a choke which acts as a current limit - the filaments are effectively on a constant current supply, not 240V!

I'm not certain but I think they are nominally 6V each, or something like that; not very high.

 

[picbits]

I predict 6 pages for this thread .......

 

[JonSea]

I predict 6 pages for this thread .......

Only 6? Common, you know 555 timers and 2N3055 are bound to make an appearance! Probably cheap batteries and some comments slandering 4 billion people too.

 

[gary350]

If filaments are 6v each that means it needs 8 D batteries. I took one of those metal tube shape starters apart once it contained a capacitor and a automatic switch. I don't remember if it was wires series or parallel and don't remember what made the auto switch work. If I have a starter I can't find it. I might find one at hardware store tomorrow. I use to have a 50 year old single light fixture I can not find it. I found this drawing online.

 

[be80be]

 

[gophert]

I hereby award gary350 20 Cool Points for recycling his original pencil and paper drawing by using an actual eraser. I would have grabbed a new piece of paper, scratched out another drawing. I wouldn't know where to find an eraser in my house.

Edit: there is an eraser by my box of old components - I use it to polish up the tarnished leads so they solder better (without flux).

 

[gophert]

But, who (yes, who) would happen to have a case of old-school 2n3055 transistors sitting around his shop to make such a circuit?

 

[be80be]

I'll loan him some

 

[be80be]

But with this bulb he could use 2 2n2222
Thats what was in the light almost the same sch just 2 2n2222 for the 2n3055