Slide switch · Exterior view
Slider leverMetal coverBasePins 1-2-3 (middle = common) · 2.54 mm spacing
Rectangular body with a small metal cover, a sliding plastic lever on top, three legs
Small body a few mm across, three pins in one row
Switches and relays

Slide switch

In simple terms
What is this?

A small switch that slides to pick one of two positions; like a sliding door.

What is it for?

Opens the circuit and keeps it open, or lets you choose one of two paths.

Where do you see it?

The on/off button of battery-powered toys and flashlights.

How do you spot it?

A small box with a plastic lever that slides sideways; three legs underneath.

Caution:

The middle leg is the common one; it is built for small currents, so don’t run a big motor straight through it.

Technical definition

A switch whose lever slides between two positions and keeps its position. In the three-leg SPDT type, the middle leg connects to the leg on one side or the other depending on the lever position. Small types exist that plug directly into a breadboard.

TypeSPDT
Position2
OperationLatching
Schematic symbol IEC and ANSI differ

IEC 60617: the drawing style used in Türkiye and Europe.

Pins 3
1Outer leg 1With the lever on this side it connects to the common leg1
2Common pin (middle)Current always flows hereCOM
3Outer leg 2With the lever on the other side it connects to the common leg2
Features typical
Type
SPDT (1 pole, 2 throws)
Number of positions
2
Current
Low; signals and small loads
Operation
Latching (lever stays in place)
Mounting
Through-hole (THT) or SMD
Example part
SS12D00 (1 pole, 2 throws)
Common mistakes
Skipping the middle legCurrent always flows through the middle pin. Connect the source or load to it.
Passing a large currentSmall switches are not made for motor current; the contacts heat up and blacken. Switch the motor with a relay or MOSFET.

Test with a multimeter

Test whether this part is good with the multimeter on the measurement screen.

Take a measurement
Where it is used
On-off in a battery circuitChoosing between two modesChoosing programming and run mode
Related lessons
How does a breadboard work?
Module 1 · From zero to your first circuitSeries and parallel
Module 1 · From zero to your first circuit
Try it in the Lab