Author Topic: Binary (additive) resistor or capacitor box  (Read 1200 times)

0 Members and 1 Guest are viewing this topic.

Offline etiTopic starter

  • Super Contributor
  • ***
  • !
  • Posts: 1801
  • Country: gb
  • MOD: a.k.a Unlokia, glossywhite, iamwhoiam etc
Binary (additive) resistor or capacitor box
« on: December 11, 2022, 05:09:43 am »
Has anyone ever made a resistor or capacitor box (thumb wheel selectable increments) which works like this:

[jumper 0 ohms] [1 ohm] [2 ohm ] [4 ohm] [8 ohm] [16 ohm] [32 ohm] [64 ohm] [128 ohm]

You'd have all those resistance values and switch them in and out of series with the other resistors to additively create any ohmic value from 0 ohms to 255 ohms. To do the same for capacitors, you'd just switch the values in and out of parallel connection with the others.

This is binary of course.

I hardly think this could be a new thing I'd thought of. Ideas?
 

Online Ed.Kloonk

  • Super Contributor
  • ***
  • Posts: 4000
  • Country: au
  • Cat video aficionado
Re: Binary (additive) resistor or capacitor box
« Reply #1 on: December 11, 2022, 06:56:02 am »
Use a 8 position dip switch.

https://www.ato.com/8-position-dip-switch

The sub 10 ohm setting precision might drive you bonkers.
« Last Edit: December 11, 2022, 06:57:57 am by Ed.Kloonk »
iratus parum formica
 

Offline etiTopic starter

  • Super Contributor
  • ***
  • !
  • Posts: 1801
  • Country: gb
  • MOD: a.k.a Unlokia, glossywhite, iamwhoiam etc
Re: Binary (additive) resistor or capacitor box
« Reply #2 on: December 11, 2022, 07:14:27 am »
Use a 8 position dip switch.

https://www.ato.com/8-position-dip-switch

The sub 10 ohm setting precision might drive you bonkers.

Hence me saying thumb wheels would be used. Yeah it would be a silly design to use DIP switches.
 

Online ledtester

  • Super Contributor
  • ***
  • Posts: 3283
  • Country: us
Re: Binary (additive) resistor or capacitor box
« Reply #3 on: December 11, 2022, 07:52:38 am »
Teardown of a IET Decade Resistance Box at 3:00:

EEVblog #211 - IET Decade Resistance Substitution Box -- EEVblog
https://youtu.be/37gYHdY0DAM?t=3m

It uses only 5 resistors per decade in a 1-2-2-2-2 pattern. It uses a custom wiper pattern to accomplish this.

I recall there being a project discussed on the forum where a custom pcb was developed for an existing thumbwheel switch and then you could get that pcb manufactured at pcbway/jlc pcb/etc. to create some sort of substitution box -- can't seem to find it at the moment.

« Last Edit: December 11, 2022, 07:54:29 am by ledtester »
 
The following users thanked this post: Ed.Kloonk

Online Ed.Kloonk

  • Super Contributor
  • ***
  • Posts: 4000
  • Country: au
  • Cat video aficionado
Re: Binary (additive) resistor or capacitor box
« Reply #4 on: December 11, 2022, 08:14:00 am »
Teardown of a IET Decade Resistance Box at 3:00:



I had forgotten about that. Gee, you're resourceful.
iratus parum formica
 

Offline Tigerwoods

  • Contributor
  • Posts: 22
  • Country: cn
Re: Binary (additive) resistor or capacitor box
« Reply #5 on: May 07, 2023, 04:57:09 am »
For binary box better use relays to handle the switching, since there are 2^n combinations that beyond the capability of mechanical switch. Google "programmable resistance box" you may find such products.
I love peace, alright let's fight.
 

Offline Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: Binary (additive) resistor or capacitor box
« Reply #6 on: May 07, 2023, 07:40:57 pm »
Has anyone ever made a resistor or capacitor box (thumb wheel selectable increments) which works like this:

[jumper 0 ohms] [1 ohm] [2 ohm ] [4 ohm] [8 ohm] [16 ohm] [32 ohm] [64 ohm] [128 ohm]

You'd have all those resistance values and switch them in and out of series with the other resistors to additively create any ohmic value from 0 ohms to 255 ohms. To do the same for capacitors, you'd just switch the values in and out of parallel connection with the others.

This is binary of course.

I hardly think this could be a new thing I'd thought of. Ideas?
It's an attractive idea, but the problem is that you'd need a thumbwheel switch that places the resistors in series. Never seen that.
Your idea would place them in parallel.
On the other hand, it would work for your capacitor box.
 

Offline Zero999

  • Super Contributor
  • ***
  • Posts: 20363
  • Country: gb
  • 0999
Re: Binary (additive) resistor or capacitor box
« Reply #7 on: May 07, 2023, 09:00:56 pm »
Just use a rotary switch for each decade.

9 x 1R
9 x 10R
9 x 100R
etc.

By the way, the original poster has been banned. Is it worth keeping the thread alive?
 

Offline Benta

  • Super Contributor
  • ***
  • Posts: 6420
  • Country: de
Re: Binary (additive) resistor or capacitor box
« Reply #8 on: May 07, 2023, 09:13:56 pm »
By the way, the original poster has been banned. Is it worth keeping the thread alive?
Really? Is that what the blue non-smiley indicates?
 

Offline tooki

  • Super Contributor
  • ***
  • Posts: 13157
  • Country: ch
Re: Binary (additive) resistor or capacitor box
« Reply #9 on: May 08, 2023, 07:26:38 am »
By the way, the original poster has been banned. Is it worth keeping the thread alive?
Based on the moderator’s comment added under the name, I guess the ban was for having multiple usernames, which is the only TOS violation they seem to enforce very diligently here. So maybe OP is still around under one of those other names.
 


Share me

Digg  Facebook  SlashDot  Delicious  Technorati  Twitter  Google  Yahoo
Smf