What is the difference between triacs and thyristors?
Answer They are essentially the same in terms of resistive loads. For inductive loads, however, back-to-back thyristors are effective. Thyristors connected back-to-back or a triac can be used for Solid-state Relay (SSR) switching elements. Thyristors and the triacs differ in their characteristics to enable the elements to adjust to a rapid rise or fall. These characteristics are expressed as dv/dt (unit: V/ μs). The dv/dt value for thyristors is greater than the value for triacs. Triacs help downsize SSRs because they can sufficiently perform switching for motors of up to the 3.7-kW class with inductive loads, and one triac element provides functionality equivalent to two thyristors connected back-to-back. Note: dv/dt is the rate of voltage rise.
