View bt137x datasheet:

Philips Semiconductors Product specification Triacs BT137X series GENERAL DESCRIPTION QUICK REFERENCE DATA Passivated triacs in a full pack plastic SYMBOL PARAMETER MAX. MAX. MAX. UNIT envelope, intended for use in applications requiring high BT137X- 500 600 800 bidirectional transient and blocking BT137X- 500F 600F 800F voltage capability and high thermal BT137X- 500G 600G 800G cycling performance. Typical VDRM Repetitive peak off-state 500 600 800 V applications include motor control, voltages industrial and domestic lighting, IT(RMS) RMS on-state current 8 8 8 A heating and static switching. ITSM Non-repetitive peak on-state 65 65 65 A current PINNING - SOT186A PIN CONFIGURATION SYMBOL PIN DESCRIPTION case 1 main terminal 1 T2 T1 2 main terminal 2 3 gate G 1 2 3