Solid State Relays (SSR)

Applications of Solid State Relays

• Industrial automation load switching and control systems
• HVAC temperature and heater control systems
• Medical equipment switching and isolation control circuits
• Telecom power switching and protection circuits
• Lighting control and building automation systems
• Motor drive and actuator switching circuits
• Test and measurement load switching systems

Key Selection Criteria

• Load voltage and current rating
• On-state voltage drop and power dissipation
• Isolation voltage rating
• Leakage current specification
• Switching speed and response time
• Input control voltage range
• Operating temperature and thermal resistance

Types of Solid State Relays

• AC output solid state relays
• DC output solid state relays
• MOSFET output solid state relays
• Zero-cross switching solid state relays
• Industrial high-power solid state relays

Thermal and Lifecycle Considerations

Solid state relays are usually selected early in power switching design because thermal management, PCB layout, and heat sink design depend on them. When a solid state relay reaches end-of-life, replacing it may require careful validation. Differences in leakage current, switching characteristics, or thermal behavior can affect load performance and system stability.

This is common in industrial automation, HVAC systems, and medical equipment where systems operate continuously for long periods. Maintenance teams often require the same solid state relay specification to avoid redesign or recertification.

Delays in sourcing compatible solid state relays can lead to production downtime, system repair delays, and increased lifecycle support costs.

Maketronics assists global engineering and procurement teams with reliable sourcing of both active and obsolete Solid State Relays.