looking for 1 transitor led flasher circuit..that works!!!!!

Manny · January 12, 2011, 01:54:32 PM

I spent some more time messing around with this today.
As I increase voltage past 12v the led would come on.

I went up by 1v at at a time, moving the pot through it's full travel at each step to see if I got any flashing.
The LED stayed constant until I got up to 18v at which point it would flash extremely quickly wherever the pot was set.

These observations hold true for all 7 of my 2N2222A's so no good news unfortunately

deadastronaut · January 13, 2011, 07:37:22 AM

'18v'..

arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.....

Manny · January 13, 2011, 12:27:09 PM

Quote from: deadastronaut on January 13, 2011, 07:37:22 AM
'18v'..

arghhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.....

Yeah I was pretty scared.

deadastronaut · January 20, 2011, 08:51:04 AM

update!..

yay!....armando kindly sent me some 2n2222's and caps (thanks a lot)..

and yay!..it works on 9v...ive still got to do the speed control but yep it works with no resistors too...

1 cap/ 1 tranny /and led/....brilliant...and it flashes without a trim/pot also..hmmmmm......

i read a few things about 'negistors' they are fussy, and prefer the can type trannies...cool.

update later guys....gotta go and do boring stuff!...

Manny · January 20, 2011, 09:40:58 AM

Quote from: deadastronaut on January 20, 2011, 08:51:04 AM
update!..

yay!....armando kindly sent me some 2n2222's and caps (thanks a lot)..

and yay!..it works on 9v...ive still got to do the speed control but yep it works with no resistors too...

1 cap/ 1 tranny /and led/....brilliant...and it flashes without a trim/pot also..hmmmmm......

i read a few things about 'negistors' they are fussy, and prefer the can type trannies...cool.

update later guys....gotta go and do boring stuff!...

That's excellent news Rob!
Did you build it exatly as per the schematic?

deadastronaut · January 20, 2011, 09:50:29 AM

hi manny, no, im using the trannie, a 470uf, and led...thats it...as configured in schemo though...

going to do the pot speed rate in a mo....

brett · January 20, 2011, 09:55:12 AM

Hi
I wonder whether a DIY transistor could be made to work. Maybe a low-voltage avalanche diode (e.g. PLVA650A with a breakdown voltage of only 4.8V) for the BE and a 1N4004 for the BC. It will always cascade, even with a 9V battery and a 3 V LED (9 > 4.8+3+0.7), and with luck it might oscillate too.
Of course, the avalanche diode might work on its own, too.
cheers

deadastronaut · January 20, 2011, 10:15:57 AM

hi brett, i have no idea!....sounds good, but alas i'm not an EE by any means.

..diy transistor sounds interesting though!..

@all yay! it works on the rate pot.(tried various values)..however when the pot is fully turned the led stops flashing and becomes very bright.compared to the flashing brightness..!

may have to whack a resistor back in there to combat this effect....but yeah, it works. nice one armando...cool.

update: right got it sorted totally...brilliant.

i have 9v into lug 1 of a 4.7kpot...then a 220r off lug 2 into collector and pos of 470uf...then emitter into pos of led...then led ground...sorted, no brightness variations
and runs very very smooth...nice. from slow to fast...

tried various resistors (in the 220r) position...varies the fast/slow rate considerably.

10k pot with 220r is as fast as you'd ever need i think...good range too...

ive got it running 2 leds fine also.....

here ya go..a pdf...

http://dl.dropbox.com/u/7464107/negistor_%202%20led.pdf

Manny · January 20, 2011, 12:41:24 PM

Quote from: deadastronaut on January 20, 2011, 10:15:57 AM
hi brett, i have no idea!....sounds good, but alas i'm not an EE by any means. ..diy transistor sounds interesting though!..

@all yay! it works on the rate pot.(tried various values)..however when the pot is fully turned the led stops flashing and becomes very bright.compared to the flashing brightness..!

may have to whack a resistor back in there to combat this effect....but yeah, it works. nice one armando...cool.

update: right got it sorted totally...brilliant.

i have 9v into lug 1 of a 4.7kpot...then a 220r off lug 2 into collector and pos of 470uf...then emitter into pos of led...then led ground...sorted, no brightness variations
and runs very very smooth...nice. from slow to fast...

tried various resistors (in the 220r) position...varies the fast/slow rate considerably.

10k pot with 220r is as fast as you'd ever need i think...good range too...

ive got it running 2 leds fine also.....

here ya go..a pdf...

http://dl.dropbox.com/u/7464107/negistor_%202%20led.pdf

I'm glad to hear it...
I feel a super duper tiny trem coming on!

deadastronaut · January 20, 2011, 12:49:28 PM

hmmmm...yeah if i can get it to dim nicely too......

ive prodded around, but no joy on dimming it while it flashes...just cuts off!..

Manny · January 20, 2011, 01:20:03 PM

I've just breaded this again following the PDF but with a 10K pot and got nothing.
Maybe my 2N2222A's are wrong or something. I'm using the metal can ones from Bitsbox and have tried all 6 that I've got.

The weird thing is, I get no voltage coming through the emitter at all.

deadastronaut · January 20, 2011, 01:40:56 PM

that is weird.....im using 16v capacitor..

i'll check the trannie later ok....

Manny · January 20, 2011, 02:05:04 PM

Quote from: deadastronaut on January 20, 2011, 01:40:56 PM
that is weird.....im using 16v capacitor..

i'll check the trannie later ok....

Cool, my cap was 16v too. $:-\$

arma61 · January 20, 2011, 02:33:35 PM

cool Rob, you too got it working!

incredible what 3 comps can do, isn't it

I wish I had more to share with you all......

@Manny IIRC I bought them from Banzai, but I'm sure it was at least 3 to 4 years ago, so little chances they still have the same batch.. but you can give a try anyway

@Rob what are you planning to do now with that

Armando

deadastronaut · January 20, 2011, 04:56:50 PM

@armando: yeah 3 components amazing...

not sure what to do with it quite yet, but i have tried it as an alternative 'tiny trem' and it seems ok...no clicking etc..
just experimenting at the moment though!......

@manny heres an interesting thread on the trannies for negistors...quite fussy by the looks of em..

http://www.diystompboxes.com/smfforum/index.php?topic=79654.0

brett · January 20, 2011, 06:09:24 PM

Hi
this is a thought straight off the top of my head...
What about applying a forward bias to the base? That might alter the voltage "gap" of the BE junction and vary the avalanche characteristics. A large-value resistor (e.g. 470k) between the emitter and the base would achieve this. Or maybe a 1M pot ?
No guarantees with this, but if it worked it could be a speed control.
cheers

deadastronaut · January 20, 2011, 06:38:56 PM

Quote from: brett on January 20, 2011, 06:09:24 PM
Hi
this is a thought straight off the top of my head...
What about applying a forward bias to the base? That might alter the voltage "gap" of the BE junction and vary the avalanche characteristics. A large-value resistor (e.g. 470k) between the emitter and the base would achieve this. Or maybe a 1M pot ?
No guarantees with this, but if it worked it could be a speed control.
cheers

hi brett this is what i did with it applying it to a tremolo..speed and depth...works ok too....

http://dl.dropbox.com/u/7464107/tiny%20miniscule%20amoeba%20tremolo.pdf

soundclip of it as on the schematic pdf

http://dl.dropbox.com/u/7464107/negistortrem.mp3

phector2004 · January 20, 2011, 06:52:52 PM

wow! 8 component tremolo?!?! I bet that could fit in a 1590-LB

deadastronaut · January 20, 2011, 07:41:57 PM

Quote from: phector2004 on January 20, 2011, 06:52:52 PM
wow! 8 component tremolo?!?! I bet that could fit in a 1590-LB

yep, fit it in ya guitar!...ha ha........

here ya go..its so small you might not see it...

http://www.diystompboxes.com/smfforum/index.php?topic=87322.380

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looking for 1 transitor led flasher circuit..that works!!!!!