Slide Switch
A slide switch is a maintained linear-actuator switch. Sliding the knob translates an internal contact bridge across stationary terminals, latching at each detent position. Both SPDT (on/on) and DPDT slide variants are common.
Inside the molded shell, a slider carries a beryllium-copper contact spring. As you push the knob, the spring rides over a series of small bumps (detents) on the housing floor, dropping into a pocket at each position. In each pocket the spring bridges two adjacent fixed terminals, completing one circuit while breaking the other.
In plain terms
A drawer that latches at two or three positions; sliding it moves a contact bridge from one terminal pair to another.
Why designers use it
- Mode select on toys, key-fobs, and small consumer gadgets.
- Low-current logic-level routing where size and cost dominate.
- Battery-eliminator vs. battery selection on test equipment.
Best for
- Mode select
- Battery on/off
- Low-current logic
Key specifications
- Current rating: 100 mA – 500 mA
- Voltage: 12 – 50 VDC
- Positions: 2 or 3
- Lifetime: 5k – 10k cycles
- Travel: 1.5 – 4 mm
When not to use it
- When you need momentary action — slide switches are latching, not pushbuttons.
- Where the user might brush past the actuator — they're easy to bump out of position.
- In high-current paths — most slide switches handle <500 mA.
Common mistakes
- Using a slide switch for mains power and discovering its 30 V contact rating.
- Forgetting to debounce the make/break — the wiper bounces several times during a slide.
- Mounting a PCB slide too close to a card edge so the case interferes with the actuator travel.
Where you will find it
- Children's toys use a 3-position SPDT slide to choose Off / Demo / On — the slider is wide enough for a child's thumb and the snap-detent gives a clear position cue.
- Old film cameras hide a slide switch under the battery door for ASA selection; the slider's contact spring routes the meter resistor network to set the film-speed bias.
- A handheld DMM uses a 4-pole slide on its mode wheel to multiplex the input jacks across resistance, voltage, and current measurement paths.
A short history
Slide switches in their modern miniature PCB form date to the 1960s and 70s with brands like CK (C&K), Alps, and APEM standardising the 7–12 mm body and 0.1-inch pin spacing. Earlier slide switches — dating to the early 20th century — used metal contacts riding on bakelite, but plastic injection molding in the 1950s made the part cheap enough for mass-produced consumer goods. The PCB-mountable through-hole slide became a catalog staple by the 1980s and the surface-mount variant became dominant after 2000.
Good to know
- Most slide switches are rated for far less current than they look like they should carry — the contact spring is tiny.
- A slide switch's detent pocket is what makes it 'latch'; without it the slider would creep between positions when the device vibrates.
- DIP switches are essentially eight slide switches in a shared housing.