TRIAC Question & Answers October 26, 2022 By WatElectronics This article lists 50 TRIAC MCQs for engineering students. All the TRIAC Questions & Answers given below include a hint and a link wherever possible to the relevant topic. This is helpful for users who are preparing for their exams, interviews, or professionals who would like to brush up on the fundamentals of TRIAC. The triode for alternating current that is TRIAC is one bidirectional device. It consists of three terminals such as two main terminals and one gate terminal. It can be used for phase control and as a high-power lamp switch. The triode for alternating current is equivalent to two silicon control rectifiers connected in parallel back-to-back and it has the same switching characteristics as silicon control rectifiers. It is widely used to control power applications to various types of loads. The current ratings of TRIAC are used up to 25 amperes, the maximum voltage rating is 500 volts, and the frequency of TRIACs is from 50 to 500 hertz. The TRIAC is a two-way silicon control rectifier that is SCR with one gate terminal. The DIAC is a two-way break-over triggering device. A DIAC and TRIAC combined package is called a quadrac. The TRIACs are used in control circuits, high-power lamp switching, AC power control, appliance-type motor drives, etc. The merits of TRIAC are it requires a single fuse for protection, it can be triggered with the positive or negative polarity of gate pulses, etc. The demerits of TRIAC are the gate current, sensitivity is poor and a well-designed RC snubber is required for protection. 1). What is the standard form of TRIAC? Triode for Alternating Current Trigger for Alternating Current Triode for Alternating Controller None of the above None Hint 2). The current rating of triode for alternating current is up to ________________? 10 amperes 20 amperes 25 amperes 30 amperes None Hint 3). The TRIAC is a two way __________________ with one gate terminal? SCR DIAC Both a and b None of the above None Hint 4). Which one of the following is a two-way breakover triggering device? DIAC TRIAC Both a and b None of the above None Hint 5). What are the applications of TRIAC? Light dimming Heating control Appliance type motor drives All of the above None Hint 6). The maximum crest working off state voltage of BTW43 is ______________________? 400 to 800 V 400 to 1200 V 600 to 1200 V None of the above None Hint 7). How many layers does TRIAC has? Two Three Four Five None Hint 8). The current rating at 85-degree centigrade mounting base temperature is _________________ in BTW43? 12 A r.m.s 25 A r.m.s 45 A r.m.s 50 A r.m.s None Hint 9). The figure shown below is an equivalent circuit of ________________? TRIAC DIAC SCR None of the above None Hint 10). How many terminals does TRIAC consists of? Two Three Four Five None Hint 11). The repetitive peak voltage rating of BTW34 is ___________________? 600 V to 1200 V 400 V to 1200 V 600 V to 1600 V None of the above None Hint 12). The breakover voltage can be controlled in __________________? DIAC TRIAC Both a and b None of the above None Hint 13). Which one of the following is a high-power device? TRIAC DIAC Both a and b None of the above None Hint 14). What is the standard form of DIAC? Diode for Alternating Current Triode for Alternating Current Diode for Alternating Controller None of the above None Hint 15). The repetitive peak voltage rating of BTW43 is ___________________? 600 V to 1200 V 400 V to 1200 V 600 V to 1600 V None of the above None Hint 16). The reliability is less in _________________ type of alternating current? DIAC TRIAC Both a and b None of the above None Hint 17). The typical value of on state forward voltage is ________________? 1 V 4.5 V 2 V 1.5 V None Hint 18). In which one of the following, the gate current can be only in direction to turn on SCR? TRIAC SCR Both a and b None of the above None Hint 19). The figure shown below is a circuit diagram of ________________? TRIAC DIAC SCR None of the above None Hint 20). The maximum voltage rating of triode for alternating current is up to ________________? 200 volts 250 volts 254 volts 500 volts None Hint TRIAC MCQ for Quiz 21). The typical value of RMS on state current non-repetitive peak is ________________? 20 A 4-40 A 60 A 70 A None Hint 22). Which one of the following one is not available in large ratings? TRIAC SCR Both a and b None of the above None Hint 23). Which one of the following is triggered by pulse of positive or negative at gate? DIAC TRIAC Both a and b None of the above None Hint 24). The figure shown below is a quadrant of ________________ triggering quadrants? Hi-Com TRIAC DIAC SCR None of the above None Hint 25). The current rating at 85-degree centigrade mounting base temperature is _________________ in BTX94? 12 A r.m.s 25 A r.m.s 45 A r.m.s 50 A r.m.s None Hint 26). Which one of the following is a low-power device? TRIAC DIAC Both a and b` None of the above None Hint 27). Which one of the following one is more reliable? DIAC TRIAC Both a and b None of the above None Hint 28). The typical value of repetitive peak off state voltages is ________________? 100 V 200 V 600 – 800 V 700 V None Hint 29). The figure shown below is a circuit diagram of ________________ trigger? Hi-Com TRIAC TRIAC SCR SCR/TRIAC None Hint Read more about SCR 30). The frequency range of triode for alternating current is up to ________________? 50 hertz 500 hertz 50 to 500 hertz 150 hertz None Hint 31). Which one of the following has longer turn off time? DIAC SCR Both a and b None of the above None Hint 32). Which one of the following has lower current ratings? TRIAC SCR Both a and b None of the above None Hint 33). The figure shown below is a circuit diagram of ________________ trigger? Hi-Com TRIAC Master/slave thyristor SCR SCR/TRIAC None Hint 34). In which one of the following, the breakover voltage can't be controlled? DIAC TRIAC Both a and b None of the above None Hint 35). The repetitive peak voltage rating of BTX94 is ___________________? 600 V to 1200 V 400 V to 1200 V 600 V to 1600 V None of the above None Hint 36). The size of triode for alternating current is ___________________? Smaller Larger Very large None of the above None Hint 37). The typical value of gate threshold current is ________________? 1.5 mA 10-50 mA 7 A 9 A None Hint 38). The commutating di/dt of BTA212-800B is _________________ A/ms? 10 A/ms 24 A/ms 45 A/ms 67 A/ms None Hint 39). How many triodes for alternating currents are used in the below circuit diagram? Two Three Four One None Hint 40). The maximum crest working off state voltage of BTX94 is ______________________? 400 to 800 V 400 to 1200 V 600 to 1200 V None of the above None Hint TRIAC MCQ for Students 41). The first angle of triode for alternating current is ____________________? 0 to 180 deg 180 to 360 deg Both a and b None of the above None Hint 42). The figure shown below is a characteristic of _______________ triac? Hi-Com TRIAC Master/slave thyristor Static triac SCR/TRIAC None Hint 43). The commutating di/dt of BTA212-600B is _________________ A/ms? 10 A/ms 24 A/ms 45 A/ms 67 A/ms None Hint 44). The size of diode for alternating current is ___________________? Smaller Larger Very large None of the above None Hint 45). The current rating at 85-degree centigrade mounting base temperature is _________________ in BTW34? 12 A r.m.s 25 A r.m.s 45 A r.m.s 50 A r.m.s None Hint 46). In which one of the following the operation is possible in four different modes? TRIAC SCR Both a and b None of the above None Hint 47). The figure shown below is a circuit diagram of ________________ trigger? Hi-Com TRIAC Master/slave thyristor Opto-isolated SCR/TRIAC None Hint 48). The off state dv/dt of BTA212-800B is _________________ volts per micro seconds? 1000 volts per micro seconds 2000 volts per micro seconds 4000 volts per micro seconds 5000 volts per micro seconds None Hint 49). The typical value of gate threshold voltage is ________________? 1.5 V 2.5 V 7 V 9 V None Hint 50). The maximum crest working off state voltage of BTW34 is ______________________? 400 to 800 V 400 to 1200 V 600 to 1200 V None of the above None Hint Please fill in the comment box below. Time's up
