High Resistance Rocker Switch or Alternative

[TinyMirrors]

I'm looking for a rocker switch or an alternative type of switch with a much higher than normal resistance between the terminals of the switch. I need to be near or higher than 250 mega ohms to ensure the device under test functions as expected. Currently we manually disconnect wires to and from the test device and that works fine, but would like to automate it a bit.

We built a simple on off switch board which can accept a device to test. We then flip a switch or two to test some functionality. I'm working with up to 200V DC but virtually no current. The device under test is very sensitive. The issue I've come across is that there the switches we used (M2012TXW25-DA) measure 25 megaohms between the different poles of the switch. This is causing issues with testing as we can't determine if the device is faulty since a current is being measured to be too high. Say ~100 nanoamps.

Measuring between pins 1 & 2 measures between 20-30 mega ohms depending on the rocker switch.

1  com  2
|----|----|

The resistance between pins 1 and 2 of the rocker needs to be much higher. ~250 megaohms or higher.

I've tested a bare pcb and I'm not able to measure the resistance between the pads the rocker is soldered to. Just in case someone was wondering.

Thanks for your advice.

[T3sl4co1l]

You mean higher off-state resistance?

Switches should be in the gigs, you have a bad part.  Try a good name brand? Different style?

Tim

[bob91343]

I agree; those values are much too low for a good switch.  Perhaps it's contaminated.

[ConKbot]

How did you clean the switch after you soldered it? The datasheet specs 1Gohm minimum, but it also says "These devices are not process sealed. Hand clean locally using alcohol based solution."

If your residue made its way inside during cleaning,that's your leakage source now.  Those switches have epoxy sealed leads, so they should be fine with local cleaning with swabs, or a controlled rinse (small nozzle, keeping the solvent under the switch, not letting it coat the switch fully)

[TinyMirrors]

The boards were cleaned with IPA. Though they may have been very sloppily cleaned. We've replaced them and they no longer register on the multimeter.

Thanks for the help guys! I would say that cleaning them properly was the best advice that worked for us.