A 5V 1-channel H/L trigger optocoupler relay module is a device that allows you to control a high-voltage or high-power circuit using a low-voltage control signal. It consists of a relay and an optocoupler, which is used to isolate the control and load circuits from each other.

The module has a single channel, which means it can be used to control a single circuit. The trigger for the relay can be either a high or low voltage level, depending on the design of the module. For example, some modules may be activated when the control input is at a high voltage level (e.g. 5V), while others may require a low voltage level (e.g. 0V) to trigger the relay.

Optocoupler relay modules are commonly used in a variety of applications where it is necessary to control a high-voltage or high-power circuit using a low-voltage control signal. They are often used to control motors, lights, or other devices in automation systems, or to provide isolation between different circuits to prevent electrical noise or interference.

This relay can be trigger by either a high-level signal or a low-level signal, making it a versatile relay that will work in most scenarios.