Circuit not working

[wysiwyg]

sucahyo, have you created one of these circuits? If so which circuit and what was the hardware you used?

Regarding the changing out of the transistor, I would still say that isn't the problem because the original circuit design by shlodo used two of the same transistors. I just think his capacitor had different ratings. I'll have to see if I can find a local shop to purchase some different parts from and will try to let you guys know what I find out. In the mean time, if anyone with more knowledge does know, please feel free to chime in!

Dave

[Richie_asg1]

I'm not sure of the circuit you are working with, but If my gut instinct is right, the capacacitor is acting as a reservoir of energy for 1/2 the cycle. A smaller cap would have available less energy to return, and a larger cap would return too much - and cause arcing/ overload. Choice then is critical to match the other components you have.
Start low, amd work up till you hit problems, then throttle back a bit

[Harvey]

What coil are you using?

Looking at Dodoshlodo's schematic, his configuration is not the normal way to use these coils - but if the transistors are only turned on for very brief periods it will approximate the same result.

The transistor configuration is a Darlington Confguration known for its very fast response curve because of the high Beta (gain) it produces. So when the device begins to turn on, it will turn on hard and fast. Turning off isn't as quick though. That is where Imhotep's relay would outperform.

These automotive coils work on the BEMF collapse of the primary field. First we charge up the primary and when we break the circuit all the energy is transferred to the secondary. So the HV terminal becomes 'live' when the circuit stops conducting on the primary. In a vehicle application, 'points' were used to break the flow at just the time we want the spark to fire.

Dodoschlodo's cap is not correctly labeled. When the primary field collapses and the secondary becomes 'live' a HV pulse discharges through the CFL in a series with that capacitor. So the positive side of the cap should go to the CFL. That pulse also raises the Base terminal of the Darlington Pair and causes a new cycle to start charging the coil.

As you might imagine, the coil inductance plays a part in the timing and resonance of the oscillation.

Now here are two things that can stop it from working for you. You may be experiencing both.

1. The Earth ground is does not drop below the transistor bias to turn off the transistors (probable, as this will cause them to burn out)

2. The Earth ground is too conductive and the CFL cannot Re-trigger.


Solution for #1. Place a 1K resistor between the Base Lead and Battery (-). This will help ensure that the transistors turn off.

Solution for #2. If your Earth ground is too clean or the wire is too thick or short, the potential on Earth can clamp your capacitor feedback. So you may need a resistor in series with the Earth ground wire, or use a smaller longer wire that allows a potential to exist across it. Remember, you are trying to get the base to fluctuate.

Realistically, adding the resistor for #1 and eliminating the Earth all together should give you good results but you will need to trigger the base to get things started at first. A separate starting resistor from B(+) briefly touched to the Base would get it going and then the Capacitor would take over from there.

Cheers!

[sucahyo]

sucahyo, have you created one of these circuits? If so which circuit and what was the hardware you used?

I don't have ground wire access here, I use 555 to switch the transistor.

80ma at 12V using transformer of a modem adaptor, 9V/240V 1A, I use the 9V as primary.
YouTube - 80mA CFL lighter

My exact spesification:


KSC5027 is much better than 2N3055.

[wysiwyg]

Brb

Sorry gang, I haven't forgotten out this project, but work has increased over these last couple of weeks forcing me off of this project temporarily. I'll be back once I get some spare time. Thanks for all those that have helped.

Dave