Slide switch connections - DP3T and DP4T

Discussion in 'Homework Help' started by ALAS, Jan 21, 2014.

  1. ALAS

    Thread Starter Member

    Sep 25, 2013
    Hi, I just have a quick question about the connections made by DP3T and DP4T slide switches. Unfortunately, I don't have one of either to test it myself and it is surprisingly hard to find this basic information on the internet. I guess it is assumed that everyone already knows.

    So with the contacts of the switches laid out like this:


    Which of the contacts are the common ones? My assumption is that is the two that I outlined in red on each diagram. Is that correct?

  2. ericgibbs


    Jan 29, 2010
    There are so many combinations of slide switches that without a part number it would be guesswork. Many do not have a Common contact, just pairs.

    Look at this pdf to see some of the options.
  3. ALAS

    Thread Starter Member

    Sep 25, 2013
    Actually, I've tracked down some data sheets for switches with this physical layout (with pairs of contacts clustered in two separate groups) and it looks like the common ones are typically the first ones in the larger cluster of contacts. That is to say, what I guessed for the DP3T was right, but for the DP4T it would be the two in the row above the ones I had thought. It actually makes more sense that way layout-wise, now that I think of it.

    It seems like when the contacts are evenly spaced however, the connections are more likely to be made between adjacent contacts as the switch slides through its positions (which also makes sense). I see what you mean about different versions functioning differently.

    Good info! Thanks!