gfxgfx
 
Please login or register.

Login with username, password and session length
logo
 
gfx gfx
gfx
19840 Posts in 1272 Topics by 5187 Members - Latest Member: charbuild October 27, 2020, 05:18:37 PM
*
gfx* Home | Help | Login | Register | gfx
gfx
Breaktru Forum  |  eCigarette Forum  |  Modding  |  Simplified Electronics  |  Topic: Changing pot resistance
gfx
gfxgfx
 

Author Topic: Changing pot resistance  (Read 5746 times)

0 Members and 1 Guest are viewing this topic.

Offline T8ternutz

  • Full Member
  • ***
  • Joined: Nov 2013
  • Location: Florida
  • Posts: 33
  • Karma: +0/-0
Changing pot resistance
« on: June 13, 2014, 07:35:06 AM »
I'm wiring up some OKR boards and cannot fin the pot I want to use in stock. I know it requires the 200ohm pot and the 93pr200lf is sold out everywhere. Can a different pot be used and the value of that pot be altered? 100 ohm and 500ohm are readily available.

Offline XombyCraft

  • Full Member
  • ***
  • Joined: Jun 2014
  • Location: NJ - USA
  • Posts: 49
  • Karma: +2/-0
  • Gender: Male
  • [¬º-°]¬
Re: Changing pot resistance
« Reply #1 on: June 14, 2014, 06:02:31 PM »
If you, or anyone else is still looking around for this answer - take a look at the "faking pot resistance" portion of this post:
http://breaktru.com/smf/index.php/topic,166.0.html

Heed the note though, that "The resulting value may fluctuate as the knob is turned.  This may be a problem in certain DC applications."

Offline CraigHB

  • PV Master
  • *******
  • Joined: Nov 2011
  • Location: Reno, Nevada
  • Posts: 2023
  • Karma: +244/-1
  • Gender: Male
Re: Changing pot resistance
« Reply #2 on: June 14, 2014, 09:51:31 PM »
You could use a 500 Ohm pot but then you lose resolution.  The voltage changes more quickly for less movement of the pot.  It would probably be okay with something like a 20 turn trimmer, but it's more likely to get jumpy with wear.  All mechanical pots do that, they get jumpy after they get too much wear on the wiper.  You wouldn't want to use a single turn 500 Ohm pot, would be too hard to get the voltage where you want it.

You could add a parallel resistor to a 500 Ohm pot to get it down to 200 Ohms, but that's kind of a fail since it makes response highly non linear.  It will change too slow at high values and change too fast at low values.

A 100 Ohm pot will not work at all since it will either cut you off for higher voltages or cut you off for lower voltages depending on the resistor you put behind it.  Though if you can live with a more narrow voltage range you can use it.  Just have to adjust the mean voltage with the resistor value behind it.

I don't understand why they use such a low value resistance to adjust the voltage output.  Makes it difficult to use any kind of adjustable value there.  I wonder if it's possible to change out the resistor on the board to allow a higher value adjustment resistor.  I bet it would be possible, would have to experiment with one.


Offline T8ternutz

  • Full Member
  • ***
  • Joined: Nov 2013
  • Location: Florida
  • Posts: 33
  • Karma: +0/-0
Re: Changing pot resistance
« Reply #3 on: June 14, 2014, 10:52:37 PM »
Thanks for the info. I placed an order for the 200ohm. Ordered enough to get them with a 3 week lead time..

Offline CraigHB

  • PV Master
  • *******
  • Joined: Nov 2011
  • Location: Reno, Nevada
  • Posts: 2023
  • Karma: +244/-1
  • Gender: Male
Re: Changing pot resistance
« Reply #4 on: June 14, 2014, 11:28:59 PM »
You can resolve just about any issue in electronics with enough money.  If I had the money, I would order a custom display for my mods, but then I need to order 1000 of them.  Two or three large is a bit much to spend just to have a custom display for my mods.  Though I've spent a good amount on custom parts, but not ~that~ much.

Offline XombyCraft

  • Full Member
  • ***
  • Joined: Jun 2014
  • Location: NJ - USA
  • Posts: 49
  • Karma: +2/-0
  • Gender: Male
  • [¬º-°]¬
Re: Changing pot resistance
« Reply #5 on: June 15, 2014, 06:49:47 PM »
Yea... unless you were mass-producing with the intent to sell... which would have been fine this time last year... but who has the $$$ to apply for FDA approval these days?

Offline Podunk Steam

  • Full Member
  • ***
  • Joined: Dec 2014
  • Location: United States
  • Posts: 44
  • Karma: +8/-0
  • Gender: Male
Re: Changing pot resistance
« Reply #6 on: December 19, 2014, 06:05:15 AM »
Bad
Boys
Blah
Blah
But
What's her name
Gives
Willingly?
Too many years back for me now, help!

Breaktru Forum  |  eCigarette Forum  |  Modding  |  Simplified Electronics  |  Topic: Changing pot resistance
 

gfxgfx
gfx gfx
Powered by MySQL Powered by PHP Valid XHTML 1.0! Valid CSS!