The SSR-25DD Solid State Relay is a single-phase electronic switching device designed to control DC electrical loads using a low-voltage DC control signal.
Featuring a 25A rated output current and 3–32V DC control input, this relay provides fast, silent switching without mechanical contacts.
It is suitable for industrial automation, DC motor control (ON/OFF), lighting systems, heating equipment, and microcontroller-based projects.
Key Features
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25A Rated Load Current: Designed for switching compatible DC loads.
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DC-to-DC Operation: Controls DC loads using a low-voltage DC signal.
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3–32V DC Control Input: Suitable for various electronic control circuits.
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Silent Switching: No mechanical clicking or moving contacts.
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Fast Response: Electronic switching for automated control.
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Long Service Life: No mechanical contact wear.
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Compact Design: Suitable for industrial control panels.
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Screw Terminals: Convenient electrical connections.
Technical Specifications
| Parameter |
Specification |
| Model |
SSR-25DD |
| Product Type |
DC-to-DC Solid State Relay |
| Rated Load Current |
25A |
| Control Input Voltage |
3–32V DC |
| Load Output Voltage |
5–200V DC (verify product label) |
| Control Input Current |
4.5–20mA |
| Switching Type |
Electronic DC Switching |
| Operating Temperature |
-30°C to +80°C |
| Dimensions |
63 × 45 × 23mm |
| Mounting Hole Spacing |
48mm |
| Mounting Type |
Panel Mount |
| Connection Type |
Screw Terminals |
| Cooling |
External Heatsink Recommended |
Terminal Configuration
| Terminal |
Function |
| 1 |
DC Load Output Terminal |
| 2 |
DC Load Output Terminal |
| 3 (+) |
DC Control Positive |
| 4 (−) |
DC Control Negative |
Note: Follow the polarity and terminal markings printed on the relay housing.
Microcontroller Compatibility
The SSR-25DD can be controlled using a suitable interface with:
- Arduino UNO and Mega
- ESP32 Development Boards
- ESP8266 Modules
- Raspberry Pi GPIO
- PLC Controllers with DC Outputs
Important: Direct GPIO operation depends on the controller's output voltage and current capability. A transistor driver or interface circuit may be required, particularly for 3.3V controllers.
Applications
- Industrial Automation
- DC Motor ON/OFF Control
- DC Lighting Systems
- DC Heating Equipment
- PLC Control Panels
- Arduino and ESP32 Projects
- Raspberry Pi Automation
- Automated DC Load Switching
Important Notes
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DC Loads Only: This relay is designed for DC-to-DC switching and is not suitable for switching AC loads.
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Polarity Sensitive: Follow the marked DC input and output polarity.
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Heatsink Recommended: Proper cooling is necessary for higher-current applications.
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25A Maximum Rating: Actual load capacity depends on operating temperature and heat dissipation.
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Inductive Loads: Use suitable flyback or transient suppression protection when switching motors, coils, or solenoids.
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GPIO Compatibility: Verify the relay input current before connecting directly to a microcontroller.
- Not intended for PWM motor speed control unless the manufacturer explicitly specifies suitable switching performance.
Package Includes
