Best way to toggle between two different cap values with no popping?

[Bucksears]

What is the best way to toggle between two capacitor values, when (the larger) one is an electrolytic and the other is not?
Was thinking about a plain 'ol DPDT with the larger cap soldered across the center lugs, and the other cap across one set of the outer lugs. (C1 and C1+C2 options)
My concern with this is that they might be out of balance, as one of the caps is polarized and the other is not.

That led me to the idea of switching C2 in series with C1 (adjusting the value of C2 to get the desired overall value when engaged). I'm trying to keep the switching effective, while avoiding popping.

Which of these (or others) would be the best practice?

 

[bean]

Polarization is not an issue. The reason for the pop in this application is the presence of DC on the switch contacts. The caps you are switching between have no DC, but the common contact (IOW, middle lug) may have DC depending on what's happening in the circuit before the switch.

One way to minimize a pop in that case is to place a large resistor across the outer lugs of the switch (at least 1M or higher). That provides enough resistance so that the caps remain isolated from one another, but any DC present at the middle lug will be distributed evenly to the outer lugs. It's not sure-fire, but it's one approach that can work. The other is to put a very large value cap leading into the switch, like 10uF, or something. That way, there's no DC at any switch contact.

 

[jwin615]

@bean
Been curious if another solution would be a "cap sandwich" of sorts.
Would that work? Would involve math but...

 

[jwin615]

There's also the cap brand approach...
I've had mixed results testing that approach out of circuit. I don't think my lcr meter liked it though

 

[flsilva]

Try this

 

[JTEX]

^or just one large resistor between the tops of the caps (across the outer contacts of the switch).