you are correct. I need to read all the post before I reply.....
EverCool Variable Voltage Mod
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you are correct. I need to read all the post before I reply.....
Not a problem. I couldnt have done it with out your posts! I just built another one with a POT. Still liking the 4.3V area!
Awesome! Thanks... you led me in the direction I needed... I'll start a thread with pics to show this circuit in use, also the ptr08060. I'm also going to try 4 batts in series and parallel (16340's?). Again, Thanks for the help... AAA
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You are very welcome... I will try to "hang" around here more.
okay so i have built this circuit to BB schematic, with the exception of a 470k ohm rsistor instead of the 220, at first, it worked and would go up to about 3.1v, so i tried "splicing" 2 of the 470's together thinking it would bring it down to 235k ohm's.....hooked it all up, when i hit the fire button it registered at .59v, tried turning the pot and didnt change voltage, so i desoldered and put the 470k by itself, now it will adjust from .60 to somewhere around 1.5 1.6v, and then jump to 7.XXX volts and make a humming noise........can somebody please help me? doing the ucc383-adj circuit was so much easier than this, im going crazy!!!
edit: the only reason i used the 470k ohm resistor is because thats all I have.
question, is the 220k ohm resistor the only one that will work?
edit: the only reason i used the 470k ohm resistor is because thats all I have.
question, is the 220k ohm resistor the only one that will work?
Are you sure it's a 470k resistor? If so, that's pretty much useless.
However, if it is a 470 ohm resistor, you can use two of them together to get 235 ohms, which should be close enough (assuming you are also using the variable resistor as in the diagram).Put them in parallel - that is side by side, with their legs touching each other. If you are using a normal PCB, you can just stick both resistors into the same set of holes.
However, if it is a 470 ohm resistor, you can use two of them together to get 235 ohms, which should be close enough (assuming you are also using the variable resistor as in the diagram).Put them in parallel - that is side by side, with their legs touching each other. If you are using a normal PCB, you can just stick both resistors into the same set of holes.
No, im not positive, i didnt realize there was a difference, its whatever madvapes includes with their LED's. Is there a way to tell? I am using it along with the 200k ohm variable resister Bourns 3299. Is there a specific reason 220ohm resister is required?
A 200k ohm variable resistor is no good.
They do however make a 200 ohm variable resistor in that same model. You didn't post the full model number, so I don't know which you have.
The K stands for kilo - which means a 200k ohm variable resistor is 200,000 ohms at max.
If the regular resistor came with an LED, it is likely 470 ohms. It would have the color bands Yellow-Purple-Brown. A 470k resistor would have Yellow-Purple-Yellow.
The reason for the 220ohm resistor is to make sure the total resistance (the 220ohm and the variable one) stays high enough for the chip to operate properly. A higher resistance gives a lower voltage with this chip - if you had about 2.8k ohms, you'd only be getting around 1v, which isn't enough to do anything useful.
They do however make a 200 ohm variable resistor in that same model. You didn't post the full model number, so I don't know which you have.
The K stands for kilo - which means a 200k ohm variable resistor is 200,000 ohms at max.
If the regular resistor came with an LED, it is likely 470 ohms. It would have the color bands Yellow-Purple-Brown. A 470k resistor would have Yellow-Purple-Yellow.
The reason for the 220ohm resistor is to make sure the total resistance (the 220ohm and the variable one) stays high enough for the chip to operate properly. A higher resistance gives a lower voltage with this chip - if you had about 2.8k ohms, you'd only be getting around 1v, which isn't enough to do anything useful.
the pot does say 200k. I ordered a pack of 5 of e bay for the ucc383-adj mod, which worked perfectly, i thought it was the same thing to use on this mod. So i twisted 2 of the 470 ohm resistors and on the meter are now reading 234ohm, so now i guess i need the different pot. BUT now my question is, how come when i used this 200k pot and the 470ohm resistor together, that I could get a 3.3v output? I also put the contacts of the meter on one of the pots, my meter does indicate that it is in fact a 200K ohm resistor. bummmmmmmmmmer. is there any other combination I could use, so that i can use these pots with this?
FWIW... If you look at my pics in post #233, I used two 470ohm resistors piggybacked with a 200ohm pot and it works fine. I love this mod!! Ive got 20 of these circuits and I'm putting them all in different types/sizes of boxes, and then selling them.
yes, but as grantemsley stated, the pot that I have is 200k ohm, NOT 200ohm. So even piggybacking my resistors with the 200k ohm pot is useless.
I was telling you that for when you DO get the right pot (200ohm) it WILL work with two 470ohm resistors... just trying to be helpful. I got my pots here... 5 x 200 Ohm 3296 trimmer potentiometer pot resistor - eBay (item 300368774480 end time Dec-13-10 18:59:32 PST) , and also the 2kohm pots that Bigblue said I needed for the pth08080wah circuit too... $4.00 for 5 pots is a good deal. I now have 220ohm resistors from the local RS... The only reasdon I didnt use them with these two first ones I made was I sent a friend to RS to get me the capaciters and the resistors and they didnt have the capacitors and he stopped there and didnt even ask about the resistors and so he told me they didnt have either... dumb friend. I since then, was in there for something else and found out they had the 220's so I bought all they had (about 40). So all my new mods will have the 220.
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Hey guys...Please double check my diagram to make sure I am not mis directing anyone here...lol
You might be able to make it work with that 200k pot...you just won't have as fine of control over it. The pot does 0-200,000 ohms. The useful range for this mod is 0-200 ohms. So there will be a tiny bit you can set it to to get the right voltage.
With the pot I have (no idea the model number, I found it in my parts bins) a half turn of the screw is about 0.15 volts. With the 200k one, a half turn would probably be the difference between 5v and too low to work. But you won't know unless you try it
With the pot I have (no idea the model number, I found it in my parts bins) a half turn of the screw is about 0.15 volts. With the 200k one, a half turn would probably be the difference between 5v and too low to work. But you won't know unless you try it
FWIW your post #233 has absolutly no value, and what does "piggybacked with a 200ohm pot" actually mean? You have 3 components, are they in series, parallel or what?
@ V Vapster
You should take a little time to understand how series and parallel affect resistance. You can then look at the datasheet and see what resistance is needed for what voltage.
Series is easy, just add them.
Resistors
For parallel it's easiest to use a calculator.
PARALLEL RESISTOR CALCULATOR
If you have 4 of the 470Ω this may work.
You would use 2 in parallel for your static @ 235Ω.
The pot in this case is used as a variable resistor. Using the parallel calculator, plunk in 200000, 470 and 470. It comes out to 234.72Ω. Connect all 3 in parallel.
You then connect the first paralleled pair, in series, with 3 paralleled components that included the pot.
Where R1 and R2 are 470Ω each and R3 will be your pot plus 2 resistor bundle.
Theoretically you'll now have a minimum resistance of 235Ω (in practice it will be a bit higher though) and a max resistance of 470Ω.
Using this chart from the datasheet, it seems you'll have a range of 3.1 - 5.5V.
I think.
Wow, thanks WillyB! That's some very helpful information, I'll see if I can get it together today.
Oh boy...sorry guys! I just double checked my POTs and they are 200 ohm NOT 200k ohm! Sorry about that guys.
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