ON-OFF-ON Question

[kurtlives]

Would having the switch on one side select 100K on the other side 20K and in the middle 120K?

Thanks...

[Zben3129]

Nope

One side is 100k

One side is 20k

Middle is off aka neither

[niggez]

If the switch is an On-Off-On switch, then the middle position of the switch doesnt connect to any contact at all. The middle lug is connected to the left lug in one positoin, and the right lug in the other.
To get your desired combinations, you would need an On-On-On switch.

                           
Like this:                         ___  O  Left Lug
                                    O                                         
                                             O  Right Lug



Edit lol i took so long to type this someone else beat me 

But if you get an on-on-on switch you could build it like this:
                                O  20k
                O  _____   O 100k
                                O 120k

With this switch you could switch between those 3 fixed resistors!

[Processaurus]

You can use your spdt center off toggle switch to get 20K, 100K, and 120K. Connect your circuit to your 20K and also one outside lug of the switch, run the other end of the 20K to the common, also solder one end of the 100K to the common, and finally solder the other end of the 100K to the other outer lug, as well as the other side of your circuit.

This puts the two resistors in series, so their resistance adds up to 120K, and the switch alternately shorts the 20K (leaving 100K seen by the circuit), in the middle shorts nothing (circuit sees 120K), and in the third position shorts the 100K (leaving the circuit seeing 20K).

Make sense?

                                   /                     
circuit----------O--VVV--0--VVV--0--------------circuit
                          20K       100K                   

0's being the switch lugs, --------'s wire

[djwackfriz]

If you look at some of the Dr. Boogey threads, there is a switch like this used for 3 different input cap values

very useful!!

[kurtlives]

You can use your spdt center off toggle switch to get 20K, 100K, and 120K. Connect your circuit to your 20K and also one outside lug of the switch, run the other end of the 20K to the common, also solder one end of the 100K to the common, and finally solder the other end of the 100K to the other outer lug, as well as the other side of your circuit.

This puts the two resistors in series, so their resistance adds up to 120K, and the switch alternately shorts the 20K (leaving 100K seen by the circuit), in the middle shorts nothing (circuit sees 120K), and in the third position shorts the 100K (leaving the circuit seeing 20K).

Make sense?

                                   /                     
circuit----------O--VVV--0--VVV--0--------------circuit
                          20K       100K                   

0's being the switch lugs, --------'s wire

Correct?

[Processaurus]

Yeah!  Electrically correct, you can save running a wire from the board to the 20K if you just run one from the board to the switch lug and connect the 20K right to the lug, like you have the 100K connected, so there are two resistors hung from the bottom of the switch.

PS I love your drawing style, one of my friend's album covers is all done with freehand spraypaint tool in like, microsoft paint.

[kurtlives]

Ahhh wonderful thanks...makes sense.

I actually found a bunch of DPDTs that I think are On On On...but I am going to try this first. Thanks for the help.