FL inverter news

[RobC]

On a recent diary post I posted a schematic for a driver circut for FL lighting. Well with more research I can say I messed up. In the circut there are no need for the diodes in series with R1 and R2 and no need for the transistors between the 555 and the Fet. Just drive the Fet directly. If R1 is 3k and R2 is 6k and C1 is .0047 it will work good. This gives you almost a square wave @20Khz. Antenna rod style transformers or E cores will both work. This circut drives 2 40 watt bulbs or 1 8ft single pin style bulb. One more thing use an amp meter as the amps should be around 3-5 amps if its working right. RobC      

[johnlm]

Thanks for the update Rob.  I was also wondering why the diodes were in there around the timing network.  Makes for a pretty simple way to power the florescents.  With the supply current being what you say it appears the unit is running with diecent effeciency.  Does one transformer (Ecore or antenna rod) work better - meaning lower supply current- than the other?

John

[TomW]

Rob;

Might be a good idea to post a comment over on the diary making folks aware of this update? Otherwise they may not see it.

Just an idea.

Cheers.

TomW

[Norm]

....or even an updated schematic....for

electronic dummies like me? Will something

like this work on tubes with burned out filaments

....or did I miss that part?  Sure would be nice

to be able to use those old burned out tubes I

got laying around here...even if they only glowed

with a 1/3 lumens as original!

      Hook em' up to a Telsa coil or a Briggs magneto?

                   ( :>) Norm.

                   

[deerslayer660]

 i made a post  back about 25 posts ago  about flouro light inverters  so seeing this post i connected my 555 ckt to one of my transformers and it takes 970ma to run

the f8t5 8w flouro  that runs on same transformer with a nte186a transistor at 480ma

 so next i tried the rod transformer littel light lights to point that i thought it would  blow but it lives funny thing lowest amp draw i could get <555 ckt is made adjustable> 2 amps ouch  its amazing how much light you can get out of that littel bulb   george

[RobC]

Hi John both style transformers pull about the same amps but I think the e-core works better. RobC

[RobC]

Will do Tom probably tomorrow or the next day along with schematics and photos. RobC

[RobC]

Updated schematic coming up in a day or two Norm. As far as burnt out bulbs I tryed one for whatever reason didn't seem to light well at all and circut amps went way up. RobC

[RobC]

Yes George at 2 amps I can just imagine how much light that little bulb put out. With a 5k pot for R1 I can reduce the amps to 2amps and still get dim but useable light out of the 8ft tube. The great thing about this style of inverter is that you could turn the power down to the point that you can just see where going or up to full power and read a book. RobC

[commanda]

Your link to projects.html on your redevices.com website doesn't render as html. Shows as text in my browser, complete with tags.

Amanda

[TomW]

Amanda;

Hmm works here in firefox and Mozilla just now? Must have been a glitch.

But thanks for the heads up.

Cheers.

TomW

[commanda]

projects.html still doesn't work for me with mozilla firebird 0.7, but does work with IE 5.

I know I should upgrade my mozilla to firefox, which I use everywhere else. It's just that I usually only fire up windows at home when I'm doing pcb layouts. I normally use Linux.

Amanda

[veewee77]

It works for me. . .

Perhaps you need to clear your cache so it will get a n ew copy. . .

[RobC]

The mosfet should be a digikey no. irf640n-nd not ns-nd. Sorry RobC

[commanda]

I posted a while back about using the main ferrite transformer out of a computer power supply. Just to report I've got one happily driving an 8 watt fluoro. One word of caution though. The core I'm using saturates very quickly at 20KHz; so I'm running it at 50KHz.

Second heads up. If you push the mark/space ratio too high, the tube goes into a forward conduction mode, and the circuit will draw heaps of current. To overcome this, put a resistor in series with the tube. I had on hand a 750 ohm 5 watt which is working fine, although a 1K 1/2 watt let the magic smoke escape very quickly.

Will post full details of what I'm doing, in my diary, in due course.

Amanda