An optocoupler triggered delay disconnect module is an electronic relay module that isolates the control signal and delays the disconnection of a load after receiving a trigger signal.

Working Principle

This module uses an optocoupler to electrically isolate the input trigger from the output relay, providing strong anti-interference capability and protecting sensitive circuits ( ). When a trigger signal (high or low level) is applied, the internal LED of the optocoupler illuminates, activating the photo-transistor, which in turn drives the relay. The relay then switches the connected load, and after a preset delay, it disconnects automatically ( ). The delay time is adjustable, typically via a potentiometer or by modifying the RC (resistor-capacitor) network. The delay can range from a few seconds up to several minutes depending on the module design. For example, a common formula for delay is T = 1.1 × R × C, where R is resistance and C is capacitance ( ).

Key Specifications

• Operating Voltage: Usually 12V DC, though some modules support other voltages ( ).
• Load Capacity: Can control AC loads up to 250V/10A or DC loads up to 30V/10A ( ).
• Delay Range: Adjustable from 0–25 seconds for small modules, or up to 0–60 minutes for high-capacity modules ( ).
• Trigger Type: Compatible with high-level or low-level pulses, and can be triggered repeatedly ( ).
• Standby Power: Minimal or near-zero, extending battery life in automotive or low-power applications ( ).

Applications

• Automotive: Delayed turn-off for reversing radar, lights, or alarms ( ).
• Industrial Automation: PLC systems, actuator control, and process automation ( ).
• Smart Home & Security: Anti-theft alarms, lighting control, and timed device operation ( ).
• Electronics Development: Robotics, electronic experiments, and prototyping ( ).

Practical Considerations

• Ensure the relay coil resistance is sufficient (typically above 300 ohms) if connecting directly to the optocoupler to prevent overheating ( ).
• The module can be powered separately from the trigger source, allowing flexible integration into different systems ( ).
• Repeated triggering during the delay period will extend the delay, ensuring the load remains active until the last trigger completes its timing cycle ( ). In summary, an optocoupler triggered delay disconnect module provides isolated, reliable, and adjustable delayed switching for various AC or DC loads, making it suitable for automotive, industrial, and smart home applications.