Optocoupler vs PhotoMOS Relay vs Solid State Relay: Selection Guide
This guide compares key parameters of three common optoelectronic device types for researchers and engineers. For detailed specifications, visit our product center.
1. Core Parameter Comparison
| Parameter | Optocoupler | PhotoMOS Relay | Solid State Relay |
|---|---|---|---|
| Principle | Electrical-optical-electrical | LED drives MOSFET | Opto-coupled TRIAC |
| Isolation | Optical | Optical | Optical |
| Isolation voltage | 2500-5000 Vrms | 2500-5000 Vrms | 2000-4000 Vrms |
| On-resistance | N/A (signal) | Several ohms (2-25) | Milliohms (very low) |
| Response time | 0.1us-4us | 0.5-5ms | 5-20ms |
| Lifetime | Long (contactless) | Very long (>10^8) | Long (contactless) |
| Max load current | < 50mA (signal) | 0.1-5A | 5-100A+ |
| Operating temp | -40 ~ +85 C | -40 ~ +85 C | -40 ~ +80 C |
2. Application Recommendations
Optocoupler
- Signal isolation & level shifting
- Communication interface isolation
- Switch-mode power supply feedback
- Data acquisition input isolation
PhotoMOS Relay
- Precision instrument switching
- Automated test equipment (ATE)
- Data acquisition channel switching
- Sensor multiplexing
Solid State Relay
- Heater temperature control
- Motor start/stop control
- High-power load switching
- Laboratory power management
3. Selection Decision Process
- Signal type: Signal transmission = optocoupler; Signal switching = PhotoMOS; Power control = SSR
- Load current: <50mA = optocoupler; 0.1-5A = PhotoMOS; >5A = SSR
- Speed: >100kHz = high-speed optocoupler; ms-level = PhotoMOS; no speed requirement = SSR
- Isolation voltage: Select based on max experiment voltage with 2x margin
- Package: DIP for prototyping; SMD for production; Module for high-power SSR
This guide is based on typical product parameters. For model-specific specifications, visit our product center. For technical support, contact us.
