SCRs - Modules SCRs - Modules are in stock at Tenco Electronics. A silicon controlled rectifier or semiconductor-controlled rectifier is a four-layer solid-state current-controlling device.SCRs are unidirectional devices (i.e. can conduct current only in one direction) as opposed to TRIACs, which are bidirectional (i.e. current can flow through them in either direction). SCRs can be triggered normally only by currents going into the gate as opposed to TRIACs, which can be triggered normally by either a positive or a negative current applied to its gate electrode.Tenco offers inventory, pricing, & datasheets for SCRs - Modules. To know more, please view our large section of SCRs - Modules below.