SLVAFU8 July   2024 TPSI2072-Q1 , TPSI2140-Q1 , TPSI3050 , TPSI3050-Q1 , TPSI3052 , TPSI3052-Q1 , TPSI3100 , TPSI3100-Q1

 

  1.   1
  2.   Abstract
  3.   Trademarks
  4. 1Introduction
  5. 2What Are Solid-State Relays?
    1. 2.1 History
      1. 2.1.1 Electromechanical Relays
      2. 2.1.2 Solid-State Relays
    2. 2.2 Isolation Technologies
      1. 2.2.1 Isolation Specifications
    3. 2.3 Relay Evolution
  6. 3Failure Mechanisms
    1. 3.1 Arcing in an Electromechanical Relay
    2. 3.2 Photo-degradation in Photo Relays
    3. 3.3 Partial Discharge
    4. 3.4 Time-Dependent Dielectric Breakdown in Capacitive and Inductive Isolation
  7. 4Electromechanical vs. Photo vs. Capacitive or Inductive
    1. 4.1 Electromechanical Relays
      1. 4.1.1 Advantages
        1. 4.1.1.1 No Leakage Current
      2. 4.1.2 Limitations
        1. 4.1.2.1 Switching Speed
        2. 4.1.2.2 Package Size
    2. 4.2 Photo or Optical Relays
      1. 4.2.1 Advantages
        1. 4.2.1.1 Lower EMI
      2. 4.2.2 Limitations
        1. 4.2.2.1 Limited Temperature Range
    3. 4.3 Capacitive or Inductive Based Relays
      1. 4.3.1 Advantages
        1. 4.3.1.1 Auxiliary Power
        2. 4.3.1.2 Bidirectional Communication
      2. 4.3.2 Limitations
        1. 4.3.2.1 EMI
    4. 4.4 Overall Comparison
  8. 5Summary
  9. 6References

2.1.1 Electromechanical Relays

Electromechanical relays were first invented in the mid-19th century. These devices functioned as electrically operated switches by using a coil in combination with movable metal contacts. These devices can experience failure as the metal contacts experience wear and tear, such as welding shut. As a result, the device has a limited number of switching cycles before experiencing complete failure, thus limiting overall reliability.

Block Diagram of an Electromechanical Relay Figure 2-1 Block Diagram of an Electromechanical Relay