CFL bulb instead of neon?

[antimony]

Hi guys.  I have been reluctant to post this question here,  but im so frustrated with my problems with my Bedini. I have made 4 or 5 Daftman Bedini circuits now and a whole bunch of coils,  but thats not what i was wondering about.

I dont want to bother you guys with that, unless there is some thread about troubleshooting i would appreciate it. 



I just wondered if you could substitute a cfl bulb for the neon bulb?  I think that i have seen or heard that you can do that somewhere.

[Pirate88179]

Hi guys.  I have been reluctant to post this question here,  but im so frustrated with my problems with my Bedini. I have made 4 or 5 Daftman Bedini circuits now and a whole bunch of coils,  but thats not what i was wondering about.

I dont want to bother you guys with that, unless there is some thread about troubleshooting i would appreciate it. 



I just wondered if you could substitute a cfl bulb for the neon bulb?  I think that i have seen or heard that you can do that somewhere.

Well, the neons I have used typically take only like 70 volts to light up whereas a cfl will take several hundred volts to light up even a little bit. I do not see this as a good substitution.  Just my 2 cents.

Bill

[antimony]

Yeah, i thought so. I made my fifth Daftman circuit today, and becouse i havent had any luck with it in the past i wanted to try making it on a wooden board like Daftman shows and see if that would work better, but no.
I tested it for continuity and it was ok,  except when i came to the neon bulb. Can it be that, or is that normal?
Im going to test the diodes tomorrow, but i dont think there is anything wrong with them.

I cant find anything wrong with the circuit, except the neon bulb, so the the problem must be my coils.
The thing is that i have wound about 5-6 bifilar coils all with a different number of turns, and with different kinds of cores. Although, all of them are wound on a plastic tube thats 20 mm in diameter. I have tried all of them, but no one seems to work.

I wasnt going to bring this up, but now i did it anyway. I guess i will figure it out with time,  but if you have experienced this yourself, please let me know how you solved it. 

[TinselKoala]

Neon bulbs are kind of special critters. They have essentially infinite resistance (open circuit) when they are not "lit" and have very very low resistance when they are lit (fully conducting.) And it takes a higher voltage to initially light them up than it takes to sustain the light. For example the commonly used NE-2 or 2a type bulb will strike at about 90 volts and remain lit until the voltage drops to about 65 volts or so. You can think of them as a kind of "spark gap" with known characteristics if you like, similar to other "GDT" gas discharge tubes but with generally lower voltages than the typical GDTs used as surge protectors, etc. Their function in the Bedini circuits is generally two-fold: first, to indicate that the circuit is working properly and producing HV spikes of voltage great enough to turn them on, and second, to protect the transistor from those same spikes by shunting them away from the transistor, either into the circuit's ground (battery negative) or into the circuit's battery positive as "recharging" or recirculating.
The neon will work on AC or DC, but interestingly it is only the negative polarity electrode that actually glows. When powered by AC it looks like both are glowing but really they are alternating so rapidly it just looks like they are both glowing.
If you provide too much current through the neon when it is glowing, the electrode material can boil off and sputtercoat the glass envelope and turn it dark, even black on the inside.
Neons like the NE-2 are often used as indicator lights in mains-powered AC circuits, with an appropriate current-limiting resistor to keep from overloading. It only takes a few milliamps of current once the neon plasma is lit, but since the plasma resistance is very low an external resistor is needed to keep from literally exploding the bulb. The neon bulb is also commonly used as a voltage regulator in older, tube-type electronic equipment. It is the prototypical "nonlinear" circuit element.
In Bedini circuits the neon is lit by very brief , relatively high voltage pulses, that is,  "inductive spikes" that come from the collapsing magnetic field of coils that are being turned off rapidly by the transistor.

So it is normal that testing a neon bulb with a DMM or continuity meter will show "open circuit" or infinite resistance.

If you want help with your Bedini motor circuit, please post the exact schematic you are using, along with details of your coils, and if possible some good photos of your setup. Also tell us what you are trying to do and what you are actually seeing in your circuit. We may be able to analyze what you've done and give suggestions for improvement.

If you post photos or diagrams _please_ size them properly, no more than 1024 pixels wide, so as to avoid screwing up the forum page formatting.

[Pirate88179]

Listen to TK here, he knows a great deal about all things electronic.

If I recall from my 3 Bedini motors I made, the neons only lit up when I disconnected the charging battery, or, if it got "full".

Here is one of them cranking up pretty fast: https://www.youtube.com/watch?v=LfprTzG5SY4

You can see in this video that even though my motor is cranking over 12,000 rpm, the neon is not lit.  But, post the stuff TK asked for and he will help you a lot.  He has built more stuff than I can dream.

Bill