# How to read Slide Switch schematics?

I can't understand the schematics of the 20pin slide switch SS44D04.

It is the first one in the pdf.

Can anyone help me?

Those parts in the middle are rigid and are attached to the slider so they move together. They have 4 positions and will short various pins depending on the position.

As you can see, the blacked-in dots that go to double contacts can be considered the common of each pole and they will each be connected to one of the four adjacent non-blacked-in dots (depending on the slider position), as in the below schematic, which I've arbitrarily numbered. You can see the four independent sections A, B, C and D. Positions are numbered 1 to 4 from left to right, consistent with the above schematic numbering.

I'll assume this is the schematic you are referring to:

The four little hollow "C" shaped things are sliders that short two pins together. They are all depicted in their left-most positions, but can be moved to three other position. Think of them as little shorting bars that all move together left/right.

This is showing you that the switch has four sliders that move together mechcanically but are electrically separate. Each slider has a common pin and one of 4 other pins it will short the common to, depending on switch position.

In the schematic above, let's number the pins starting with 1 in the lower left corner and going counter-clockwise (like when you're looking down onto a IC mounted on a board).

Pins 1-5 are all related to the lower left slider. The slider can be in 4 different positions. Pin 3 is the common. In left to right slider position order, either pin 1, 2, 4, or 5 is connected to pin 3.

Pins 6-10, 11-15, and 16-20 are each for a different slider. Each has its own common, and its own set of 4 pins that will be connected to the common depending on slider position.

This could be called a 4P4T switch, meaning 4 pole (number of sliders) 4 throw (number of positions for each of the sliders).

The four elongated horseshoes are the shorting bars. As they move along they short different throws (the hollow circles) to the poles/common pins (the filled circles). Since this is a 4P switch, all four shorting bars move the same distance at the same time. The position of the circles in the schematic reflects the locations of the physical pins on the switch itself.