Author Topic: 12V FL light experiments  (Read 2731 times)

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RobC

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12V FL light experiments
« on: March 06, 2005, 04:04:38 AM »
Well after many hour of painstaking research at various web sites I think I have a decent design. Here what we have, a 555 timer circut running just above the audible range less than 50% duty cycle driving a npn x pnp transistor totem pole driving the gate of a ifr 640 mosfet which is hooked up to ferrite tranformer. The transformer is a little small 1 5/8 x 1 5/8 x3/4 (hard to wind) the secondary is wound first 500 turns each layer insulated with several layer of clear tape, wire size .40mm (26 awg). Primary is according to the spool 17.00 awg which seems a little odd or 1.21mm according to my calipers. it consists of 18 turns one layer. The transformer is running a F96T12.CW single pin bulb at full brightness @5 amps 12v. This bulb is 8ft long by the way. All components are only slightly warm. Step 2 find bigger ferrite transformers that are easier to wind, off to ebay I guess! RobC
« Last Edit: March 06, 2005, 04:04:38 AM by (unknown) »

monte350c

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Re: 12V FL light experiments
« Reply #1 on: March 05, 2005, 10:21:28 PM »
Hi Rob,


These fluorescent light experiments have my interest! I have not played with these things at all - but sounds like you're getting results.


I've been reading BTHumble's posts as well.


A couple of questions. I have a reasonable understanding of 555 circuits and could set one up for let's say 15khz without much trouble. You're driving the xformer through the mosfet.


Where did the transformer come from? Did you rewind it - I see you're spec'ing 500 turns per layer for the secondary - how many layers are there?


Finally - I am guessing this circuit cold strikes the tube so no need for any special starting provisions?


Thanks!


Ted.

« Last Edit: March 05, 2005, 10:21:28 PM by monte350c »

RobC

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Re: 12V FL light experiments
« Reply #2 on: March 06, 2005, 08:27:52 AM »
The transformer was the largest E core ferrite type I could find from old computer monitor. Secondary winding are 4 layers 500-600 turns total. No need for a special start circut tube lights instantly. I will try to post a schematic later. Hopefully this circut will prove to have long term reliabilty and be something everybody can build. At least thats my goal.RobC
« Last Edit: March 06, 2005, 08:27:52 AM by RobC »

RobC

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Re: 12V FL light experiments
« Reply #3 on: March 06, 2005, 08:38:20 AM »
Forgot to mention I found some Ferrite E cores on Ebay. I bought 2 with the plastic bobbins that hold the wire for 8.00$. Can't hardly wait to get them and start winding wire should be easier as they are bigger than the one I'm using.RobC
« Last Edit: March 06, 2005, 08:38:20 AM by RobC »

monte350c

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Re: 12V FL light experiments
« Reply #4 on: March 06, 2005, 11:51:46 AM »
Thanks Rob, looking forward to your next posts!


Ted.

« Last Edit: March 06, 2005, 11:51:46 AM by monte350c »

deerslayer660

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Re: 12V FL light experiments
« Reply #5 on: March 06, 2005, 01:18:42 PM »
   i am also working with b t humbles ckt seams ok with 40 watt bulbs using tip3055

 but whin i tried using 2 25 watt tubes in searies  the transistor got hot and light output went down conciderably  so i went to a  c1050 trans i had in junk box witch would not light the tubes fully  so i tried a 2n3055 i bought 2 of these and blew bolth they work ok with 12vdc but at 14.5 charge voltage of motor home thats the end of these transistors my goal is lowest current draw and able to work at 11 - 15 vdc input as i need motor homr running wile microwave is in use off the inverter i know i can just turn off light wile running engine but hate to compermize  will your new

ckt work  for my application?  am also interested in you ckt print thanks george
« Last Edit: March 06, 2005, 01:18:42 PM by deerslayer660 »

RobC

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Re: 12V FL light experiments
« Reply #6 on: March 06, 2005, 08:15:05 PM »
 I used to use 2n3055's in my circuts untill I started experimenting with mosfets. As far as I tell when 2n3055's die the mosfets will still be going strong and begging for more. AS for the 11-15 volts this circut should be just fine. But its one of those things we will have to try. Once the schematic is posted all of the other electronic guru's can added their 2 cents. I actually look forward to it because we have some very smart people on this board. RobC
« Last Edit: March 06, 2005, 08:15:05 PM by RobC »

commanda

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Re: 12V FL light experiments
« Reply #7 on: March 09, 2005, 02:46:34 AM »
Did you have a flyback diode across the 2N3055? Most fets seem to have them inbuilt. Bipolar transistors don't.


Amanda

« Last Edit: March 09, 2005, 02:46:34 AM by commanda »