Circuitbenders Forum

Please login or register.

Login with username, password and session length
Advanced search  

News:

Author Topic: Hello: A question about pots  (Read 4846 times)

geigercounter120

  • Newbie
  • *
  • Karma: 1
  • Offline Offline
  • Posts: 16
Hello: A question about pots
« on: July 05, 2006, 01:56:31 PM »

Hi everyone; this is my 1st post here so apologies if I'm posting in the wrong place.

I'm just starting out in circuit-bending and am sourcing a set of components and tools.  I was wondering if anyone here knows a place/shop in the UK that stocks 'high power' pots (in the region of 5 - 10M)?

Cheers and hello!
 ;D

Chris
Logged

Signal:Noise

  • Closer to the meat
  • *****
  • Karma: 16
  • Offline Offline
  • Posts: 291
Re: Hello: A question about pots
« Reply #1 on: July 05, 2006, 09:41:49 PM »

You can solder resistors in series to increase the value of a pot if you have trouble sourcing some.
Logged

geigercounter120

  • Newbie
  • *
  • Karma: 1
  • Offline Offline
  • Posts: 16
Re: Hello: A question about pots
« Reply #2 on: July 06, 2006, 02:42:34 PM »

You can solder resistors in series to increase the value of a pot if you have trouble sourcing some.
Thanks for that; a quick (massively newbie) question tho: how would placing resistors in series allow me to use them as variable resistors (in the manner of pots)?
[The reason I'm asking is that I was reading the Ghazala book and am planning to have some fun with a play-a-sound book strip in order to create some nice ambient noize (as one of my first ever bends!), but instead of using, for example, one resister just to pitch sounds down, I'd like to be able to alter the pitch to extremes...]

Thanks for your help ;D
« Last Edit: July 06, 2006, 03:00:24 PM by geigercounter120 »
Logged

iqoruvuc

  • Dayglo Volunteer of International Masturbation
  • ***
  • Karma: 10
  • Offline Offline
  • Posts: 106
Re: Hello: A question about pots
« Reply #3 on: July 06, 2006, 03:55:57 PM »

It would do but the pot wouldn't be able to go any lower then the resistor you put in series with it.  So if you use a 1 Meg pot without a resistor you have a range of 0 ohms up to 1M Ohms.  However if you add a 1 Meg resistor in series to the pot then you will have a range of 1 Meg Ohms up to 2 Meg Ohms because the current will be running through a 1 Meg resistor before it has even reached the pot.

This may work for what you want to do or not.  Keep in mind that whenever you add a pot you nearly always have to add a resistor in series to a pot because too little resistance (or none if the pot is turned right to the end) will crash the circuit.  Similarly though too much resistance can crash it so ideally you want to be able to turn the pot to its fullest resistance without it crashing so you don't crash it mid performance, and therefore putting a large Ohm resistance in series with the pot may make the overall resistance too much.  Saying that though you sometimes have to make compromises, and do whatever creates the best sounds!

What resistor are you replacing by the way?  I have never needed a pot as high as 5 meg on any of the projects I have completed although 1 meg is often to low.  You can get 2M2 pots at rapid but they have a diametre of 20mm!
Logged

geigercounter120

  • Newbie
  • *
  • Karma: 1
  • Offline Offline
  • Posts: 16
Re: Hello: A question about pots
« Reply #4 on: July 07, 2006, 09:36:26 AM »

cool, that makes sense now cheers!

I'm not sure what resistor I'm replacing as yet: I'm waiting for the adventures of The Incredibles play-a-sound book to arrive from ebay (sounds like a good read too  ;) )

Like I say, I'm only going by what the Reed Ghazala book said and the book strip project called for 10M... though it may well be a typo...>?
I'll have a look around for lower value pots that won't eclipse the circuit itself!

Thanks again,

Chris
Logged

iqoruvuc

  • Dayglo Volunteer of International Masturbation
  • ***
  • Karma: 10
  • Offline Offline
  • Posts: 106
Re: Hello: A question about pots
« Reply #5 on: July 07, 2006, 02:08:53 PM »

No it's probably right I just haven't bent one of those books yet.  I have a 'Spot' the dog book but haven't got round to ending it yet.
Logged