The transient suppression diode is directional, unidirectional and bidirectional. How to distinguish the direction of the transient suppression diode?

A simple and intuitive way is to look at the surface of components. If there is a cathode line on the surface, it is a unipolar TVS tube. It is unidirectional, otherwise it is bidirectional; You can also see the model. For the SM830A and SM8S30CA mentioned above, it can be seen that A behind the model tail represents one-way and CA represents two-way. Of course, you can also check the product manual and borrow a multimeter to test!

What is the difference between single and bidirectional transient suppression diodes?

1. The current curve is different: the forward characteristic of unidirectional TVS tube is the same as that of ordinary voltage stabilizing tube, and the reverse is PN junction avalanche device; The forward and reverse directions of bidirectional TVS tubes are PN junction avalanche devices.

2. The junction capacitance is different: the junction capacitance of unidirectional TVS is larger than that of bidirectional TVS.

3. Different applications: unidirectional TVS is generally used in DC circuits, and bidirectional TVS is generally used in AC circuits.