Switchs

Switches are everywhere — from your light switch at home to the buttons on your favorite gadgets. They might look simple, but there’s a wide variety designed for different uses and control needs. Let’s take a look at the most common types of switches and what makes each one unique.

Basic Mechanical Switches

  • SPST (Single Pole Single Throw): The simplest type — turns a circuit ON or OFF.
  • SPDT (Single Pole Double Throw): Routes current between two outputs; great for selection control.
  • DPST (Double Pole Single Throw): Controls two separate circuits with one switch.
  • DPDT (Double Pole Double Throw): Can reverse current direction or control two circuits independently.
  • Momentary Switch: Active only while pressed — like a doorbell.
  • Toggle Switch: Flips between ON and OFF positions using a lever.
  • Rocker Switch: Rocks back and forth; often found in power panels.
  • Slide Switch: Moves sideways to open or close a circuit.
  • Rotary Switch: Rotates to select one of many output positions — perfect for mode selection.
Chart showing various types of electrical switches with symbols and examples for each type.
This chart provides a visual overview of different electrical switch types such as SPST, SPDT, DPST, and DPDT, along with their circuit symbols and basic functions.

Special Purpose Switches

  • Pushbutton (PB) Switch: Activated by pressing; used for temporary or latching control.
  • Limit Switch: Triggered by a moving part — commonly used in machinery.
  • Micro Switch: Tiny and ultra-responsive; detects slight movements.
  • Reed Switch: Operated by a magnetic field — used in sensors and alarms.
  • Pressure Switch: Responds to air or fluid pressure changes.
  • Float Switch: Detects liquid levels, useful in sump pumps and tanks.
  • Thermal Switch: Reacts to heat to protect circuits from overheating.
  • Key Switch: Operated by a key for secure access or safety lockout.

Electronic and Sensor-Based Switches

  • Relay (Electromagnetic Switch): Uses an electromagnet to control high-power circuits.
  • Transistor Switch: A solid-state electronic switch that controls current using voltage.
  • Optical Switch: Activated by light; ideal for automation and sensing applications.
  • Proximity Switch: Detects nearby objects without touching them.
  • Touch Switch: Activated by human touch or a change in capacitance.

Switches are like the language of control in electronics — they tell circuits when to start, stop, or change direction. Whether mechanical or electronic, each type plays a role in turning your ideas into real, working systems.