Metku.net

Hi all,

I've built the circuit twice now and still can't get it to work! I'm building it straight from the circuit diagram with two transistors (2N3904 & 2N3906) and just nothing whatsoever happens.

Can you give me any pointers to test the circuit so I can try figure out where I'm going wrong or if any of my parts are broken.

Problem solved - read end of thread

Cheers
Mike

To see if the 324 is giving out any signal, place a led from pin 1. that the transistors are now connected and see what it does. It should fade that single led. If not, there is something wrong with the timing part (resistors etc.). If it fades that single led, you have something wrong with your transistors.

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Main Computer: Intel i5, MSI H55M-ED55, 12 Gigabytes of DDR3, 3 Terabytes of HDD, GTX295 and Benq 27"

Thanks for responding. I tried that and nothing happened, so I'm looking into the timing circuitry at the moment. A few questions if you don't mind:
1) I'm using 6V (two 3V batteries). Does that make a big difference?
2) The resistors I have are massive, I mean they are bigger than the IC, have I bought the wrong ones? They are def the right omage, and also when I attach them to a single LED I do get some glow.
3) My capacitor says 35V on the side of it, does that mean that it will only work @ 35V?

Physical size of the resistors do not matter. Also the voltage rating of the cap is not an issua. It basically needs to be 2*supply voltage and this is covered nicely in your case.

Can't see anything wrong with your components from your post... sorry, you just need to dig deeper.

_________________
Metku | AlltheMods | LedCalc | Teknolelu | AndroidCoding
Main Computer: Intel i5, MSI H55M-ED55, 12 Gigabytes of DDR3, 3 Terabytes of HDD, GTX295 and Benq 27"

Are you sure that your LM324 circuit is the right kind? I mean that if it's wrong type, then it requires double sided power supply (for example +6V AND -6V).

I believe it is, it says LM324N on it - it's this one: http://www.maplin.co.uk/Search.aspx?cri ... D&DOY=31m7

I think I *may* have solved the problem though - it could be the resistors, they go like this:

"47k" - Brown (gap) Red Black Purple Yellow/Gold
"100k" - Brown (gap) Orange Black Black Brown

According to http://samengstrom.com/nxl/10116/5_band ... ge.en.html

the 47k one is 1200M - although it looks identical to the one in the picture from the colorfade page

and the 100k one is 130 omhs.

So I'm a bit confused!

No, wait, I think I was doing it back to front - the resistors do seem to be fine.

I think there still could be a slight chance that it needs double sided power supply. Because the N-types are often that kind, depending on manufacturer. Test it with +6v and -6v. It can easily be done with four 3v batteries. In the middle you have ground and on the other end +6v and on other end -6v, if you know what I mean?

Ok, so I solved first problem - it had to do with my battery pack underpowered.

So now, the LED on the NPN comes up - sometimes it seems to fade in although quite quickly. Measuring the voltage across it, it does appear to rise in value. Then nothing else happens.

What I'm trying to figure out here is, what actually makes this thing cycle? Because the transistors appear to be correct.

One thing that may lend some clue - if I take the blue 100k and put a POT on it and turn it right the way down to zero, then both LEDs come up. The one on the PNP comes up very bright and as soon as I just turn the POT a little but to create some resistance, then the PNP goes out and the NPN comes on.

Ok, solved had followed earlier advice and switched around the resistor on 5-7, I switched it back and everything worked. So at the end of the day it was just down to not enough voltage!

Thanks everyone for their contributions, I'll post a video of my light in all it's glory after this weekend's camping.