On/off/on dpdt parallel/series resistors

[rangermaster]

Hi there

Is it possible to make a on/off/on dpdt switch to switch between 3 resistors ?

I want one position to be 68k
The second 82k
And the third 42k

I think i have to wire resistors in parallel with this switch but maybe some of you have an excellent idea ?

Tnx

[GGBB]

Yes - if you are okay with being 40ohms (0.05%) off for the 82k position, and using a 27k and 15k in series for the 42k.



Effective R:
68k switch up
82k in center
42k (27+15) switch down

Up - the 56k and 27k+15k  are shorted
Center - 56k in series with 68k and 42k in parallel
Down - 56k and 68k are shorted

[rangermaster]

Yes - if you are okay with being 40ohms (0.05%) off for the 82k position, and using a 27k and 15k in series for the 42k.



Effective R:
68k switch up
82k in center
42k (27+15) switch down

Up - the 56k and 27k+15k  are shorted
Center - 56k in series with 68k and 42k in parallel
Down - 56k and 68k are shorted

thanks for the reply!

but if i put them in parallel like this:

on-off-on dpdt switch
⦿--[100k]--⦿ position 1 should be 45k
⦿---[82k]---⦿   position 2 stays 82k
⦿--[300k]--⦿ position 3 should be 64k

right? after calculations.

[GGBB]

Sure - if you don't need precision. You also don't need a DPDT - SPDT will do. That would be a whole different question than what you asked. 

[rangermaster]

Values are just an example.

It was about the switch wiring

[GGBB]

It was about the switch wiring

Right - so values don't matter and even the switch type doesn't matter. Then you can pretty much do anything you want since there are no rules - and no need to ask.

[rangermaster]

Switch does matter. Read first post.

Dpdt on/off/on.

Values don't because of bias setting that i will measure later.

Question was about the "dpdt on/off/on" switch wiring.

indeed

[GGBB]

Read first post.

I did - read second post.

[PRR]

...SPDT will do. ...

That would be two positions. He wants three positions.

Single-pole is fine, but triple-throw is mandatory? Even if one "throw" is just a no-connection?

[rangermaster]

Read first post.

I did - read second post.

not my post. i talked about a dpdt.

no need for discussions.

[rangermaster]

...SPDT will do. ...

That would be two positions. He wants three positions.

Single-pole is fine, but triple-throw is mandatory? Even if one "throw" is just a no-connection?

i don't have spdt in stock. only dpdt.

i tried a few parallel connections yesterday and it work fine.

thanks for the help.

[FiveseveN]

But do you understand that you can use a DPDT as a SPDT (leave half unwired)?

[rangermaster]

But do you understand that you can use a DPDT as a SPDT (leave half unwired)?

i do thx

[GGBB]

...SPDT will do. ...

That would be two positions. He wants three positions.

I should have been more specific - SPDT on-off-on.