Switch interfacing Part-7
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This document discusses different types of switches used to control electrical circuits. It introduces single pole single throw (SPST) switches, which have a single input and output contact to open or close a circuit, and single pole double throw (SPDT) switches, which have one input but two output circuits where only one is energized at a time. Some specific switch types covered include toggle switches, slide switches, rocker switches, momentary switches, ganged switches, mercury switches, electromagnetic switches, position switches, and pressure switches.
Switch interfacing Part-7
- 2. Introduction to different types of switches. www.techvilla.org.in
- 3. To open and close a circuit Open (no connection) Closed (connection) Control device Does not consume power www.techvilla.org.in
- 4. Pole- what the switch armature is connected to Pole Throw •• ThrowThrow- the closed position of- the closed position of the switchthe switch www.techvilla.org.in
- 5. Different types of switches: “SPST” – Single Pole / Single Throw “SPDT” – Single Pole / Double Throw Ganged Switch (MPMT) Mercury Switch Electromagnetic Switch Position Switch Pressure Switch www.techvilla.org.in
- 7. RockerRocker Push On/OffPush On/Off www.techvilla.org.in
- 9. SPST Switches Single pole input Single pole output A set of contacts inside the switch opens or closes the circuit The contacts carry the current load of the circuit when closed www.techvilla.org.in
- 10. The “Momentary” Switch A SPST type switch Switch contacts are spring loaded Closing the circuit requires overcoming spring pressure Circuit is opened by spring Switch is (NO)www.techvilla.org.in
- 11. SPDT Switches One input circuit (pole) Two output circuits (throws) Only one output is energized at a time Contacts carry the current load of circuit www.techvilla.org.in
- 12. Ganged Switches (MPMT) Contain multiple “wipers” that operate in unison Contacts may carry current load of circuit Contacts may supply current to an “electromagnetic switch”www.techvilla.org.in
- 13. Mercury Switches A SPST type switch Uses mercury as the conductor for the contacts Accurate mounting of mercury switches is essential to proper operation Used on ground side of circuit www.techvilla.org.in
- 14. Electromagnetic Switches Also called a “relay” Uses a small amount of current to control a higher amperage circuit Relays are (NO) type circuits Often controlled by low amperage switch circuitwww.techvilla.org.in
- 15. Position Switches May be used on power or ground side of circuit Used to indicate whether a component is in the on or off position Only provides a “high/low” signal to a solid state control device A low current circuit www.techvilla.org.in
- 16. Pressure Switches Can be used on either power or ground side of circuit Switch is turned on/off by “pressure” rather than a component’s movement Switch may carry current load of circuit Switch may be used as a type of position switch for a solid state control device www.techvilla.org.in