Difference between TRIAC output and SCR output in solid-state relays:

1. Trigger method:

-Triac (bidirectional thyristor) can be triggered to conduct in both positive and negative half cycles of the AC cycle, and the trigger signal can be applied at any time of the AC power supply.

-SCR (silicon controlled rectifier) can usually only be triggered to conduct during the positive half cycle of the AC power supply.

2. Shutdown feature:

-TRIAC can be turned off by applying a reverse voltage or reducing the current to below the holding current.

-Once SCR is turned on, it cannot naturally turn off unless the current decreases below the holding current.

3. Applicable load types:

-TRIAC is suitable for various types of loads, including resistive, inductive, and capacitive loads.

-The control performance of SCR for inductive loads may be relatively poor.

4. Control accuracy:

-TRIAC generally performs well in terms of control accuracy and can more accurately control the conduction angle.

-SCR may have slightly lower control accuracy in some cases.

5. Price:

-Under normal circumstances, the cost of solid-state relays for SCR output may be relatively low.

综上所述，在选择固态继电器时，应根据具体的应用需求和负载特性来决定是采用 TRIAC 输出还是 SCR 输出的产品。