This post explains for the triac.
The Part Number is BTA41-600B.
The function of this semiconductor is 40A, 600V, Triac.
Manufacturer: ST Microelectronics
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Available in power packages, the BTA40, BTA41 and BTB41 are suitable for general purpose AC switching. When used with the properly dimensioned heatsink, the BTA40, BTA41 and BTB41 can enable AC switching systems up to 9 kW. Refer to ST Application Note AN533 for thermal management of Triacs.
The BTA40, BTA41, BTA41-600B and BTB41 provides an insulated tab (rated at 2500 V rms). They are recognized by UL. Representative samples of these components have been evaluated by UL and meet applicable UL requirements for UL 1557 standard (File Ref. 81734).
• High current Triac
• Low thermal resistance
• BTA40 and BTA41 UL1557 recognized components (file ref: 81734)
• RoHS (2002/95/EC) compliant packages
• UL-94, V0 flammability package resin compliance
• On/off function in static relays, heating regulation, induction motor starting circuits
• Phase control operations in light dimmers and motor speed controllers