Circuit not working, transistor heating up?

Hey guys, I made this circuit (diagram attached) but it isn't working. There is no output voltage and the transistor is heating up like crazy.

Some differences in my circuit:

1- I got my transformer from an LED bulb and not a camera.
2-I'm feeding it 3v for testing.
3-The NPN transistor I used is 2N3904.
4-Im using 2 100 ohm resistors in series instead of one 220 ohm.
5-I didnt attach a potentiometer,
6-I couldnt find a capacitor like that so I used a polyster 400v 473J capacitor.
7-My diode is not a schottkey one but a 1N4007 diode.

I double checked al my connections and there are no shorts.

Picture of Circuit not working, transistor heating up?
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shahryar.adil.3 (author) 1 year ago

Well turns out the transistor was heating because it was shorted. Thats fixed, but the circuit still isnt wortking :/ I can prove the ohm ratings or whatever of the transformer if you need it

Just two of ten possible configurations.

Disconnect the XFMR (transformer) and Please measure ohms between pins

1-2,6-5,6-4,6-3,5-4,5-3,4-3,1-6,1-5,1-4,1-3,2-6,2-5,2-4,2-3 and your meter shorted probes to each other...

q6.JPGCopy of q4.jpgq5.jpg

You probably need a new transistor, Check eBay

We still a) need to know what you expect this to do

b) we need to see your actual build.

shahryar.adil.3 (author)  rickharris1 year ago

Kind of a shocker. That but with a 6 pin transformer.

Therein lies a problem, if your not using the identical components then whether the circuit works may be a gambol. electronics is like that, sometimes you can get away with it and some times not.

In this circuit the transformer is critical to it's operation. Problem solved I think. get the right components.

Yonatan241 year ago

You probably need a new transistor, Check eBay

What on earth is it supposed to do ? It looks like a random assembly of parts.

I see what looks like a classic self oscillating transistor circuit that generates a few huntred volts.

Anywhere near that little transistor ? Really ?

And how is the base of the transistor connected ?

What is the picture of the camera for ?

I think the camera symbolizes where this circuit came from, or possibly what it is intended for, specifically, for charging the capacitor for the camera's flash.

Yes. I also noticed this "circuit diagram" is lacking in useful information, like details about the {emitter, base, collector} connections to the transistor, and also the windings of the transformer.

At the same time, this diagram maybe has information that is useless, or redundant, like the words "Red Red Brown Gold". Hmmm...

Well, whatever it is, I don't want to step in it.

"Across that little transistor ? Really ? And how is the base of the transistor connected ?How do we get a transformer capable of that from an LED driver ?"

You're right, and I pointed those flaws out in my answer to the question. I guess you deleted this comment already though since you saw my answer after replying lol.

I assume the LED driver was driving something like 30-50 LEDs in series from AC. I have a decommissioned large LED streetlight that uses something like 48 CREE XR-E LEDs and the inverter had rated output of 100-400V @ 350mA. Assuming this is a constant current driver. Assuming the setup is something similar. Even if it is not rated for it, I find it pretty easy to get a few hundred volts out of a even audio transformers due to the flyback princible.

-max- -max-1 year ago

Huh, now your comment appears. Instructables is so slow...

Crystal ball says it's supposed to charge the cap up to 400 volts.

But I assume this isn't what was built. Be nice to see that.

-max-1 year ago

There is not enough information in this question to tell you what's wrong. I ASSUME you are attempting to build a joule thief with a high voltage secondary or copy the circuit inside the camera to generate high voltages. I have found a few problems, listed below:

* I have no clue how that transformer is wound, and you have no clue how that transformer is wound. This is most likely your problem. So you will need to verify how it is wound or, more likely, rewind it. You need to understand how the circuit oscillates and a bit of transformer theory to do that. This might be as simple as swapping connections to the transformer around a bit to see if you can get it to work.

* I am 80% confident that the circuit is wired wrong. It looks like too much current will be flowing through the base of that small, poor transistor. There is no current limiting resistor between the base and emitter.

* TO92 transistors don't have standardized pinouts. Verify the pinout with a transistor tester or a datasheet. If you pulled a transistor out of a random device, how can you be sure that it is the right type? I assume you need a NPN switching type, but if you are salvage parts, you might have end up with a FET, a SCR, thyristor, triac, or even some sort of digital sensor! You claim that it is a 2N3904, but that is probably one of the crappiest transistors you can use for this type of circuit. It can only deal with up to 200mA of current. Many other transistors in the same form factor can deal with >3 times more current (600mA-1A) even in the same TO92 package. (a 2N2222 or a 2N4401 would be a much better choice. For more power, a TIP31c or MJE3055 are good and robust.)

* TO92 in my experience are very unforgiving to misteaks and transistors die pretty easily. If it is overheating it is likely dead. For prototyping, either get hundreds or thousands quantity of cheap transistors, (a full ziplock baggie), or use big power transistors. I generally use TO220 type transistors. For many circuits, they are overkill, but they are forgiving to mystekes. You can then use a TO92 device if you want a permanent circuit.

*In my experience, 3V is too much for these crap-tacular circults. I am even more sure your transistor is dead.