• 0.482
• 0.8l2
• l.ll
• 1.21
• #### 2.  A triac can pass a portion of …………… half-cycle through the load

• Only positive
• Only negative
• Both positive and negative
• None of the above

• 100Hz
• 50Hz
• 25Hz
• 500Hz
• #### 4.  A semi-converter circuit gives the following voltage waveform. Find the expression for the average output voltage with Vs = Vm sinωt and firing angle α

• (Vm/π) cosα
• (Vm/π) (1+cosα)
• (2Vm/π) cosα
• (2Vm/π) (1+cosα)
• #### 5.  A simple diode rectifier has ‘ripples’ in the output wave which makes it unsuitable as a DC source. To overcome this one can use

• A capacitor in series with a the load resistance
• A capacitor in parallel to the load resistance
• Both of the mentioned situations will work
• None of the mentioned situations will work
• #### 6.  Apakah fungsi satu diod beroda bebas?

• Diod ini membekalkan voltan keluaran DC yang tetap
• Diod ini menghalang penyongsangan voltan pada beban semasa separuh kitar negatif bekalan masukan
• Diod ini membenarkan pelarasan voltan keluaran denganpengawalan sudut picuan
• Diod ini mendapatkan voltan keluaran yang sama nilainya

• T1 and T2
• T2
• T3 and T4
• T4
• #### 8.  In a LC filter, the ripple factor,

• Increases with the load current
• increases with the load resistance
• remains constant with the load current
• has the lowest value
• #### 9.  Litar penukar AC – DC yang menggunakan kombinasi Diode dan Thyristor dikenali sebagai :-

• Litar penerus terkawal sepenuhnya
• Litar penerus berinduktif
• Litar penerus separuh terkawal
• Litar penerus tak terkawal
• #### 10.  For the given circuit, when the devices T1 and T2 are conducting from ωt = α till they are naturally commutated at π voltage across the other two pair of devices is

• zero
• positive( forward voltage)
• negative (reverse voltage)
• None of the above
• #### 11.  Di antara kebaikan peranti semikonduktor dalam litar penerus ialah:-

• Mempunyai bahagian bergerak
• Lebih getaran
• Kos rendah
• Mudah dibaiki
• #### 12.  What electrical component is used to smooth half wave current signals?

• Resistor
• Diode
• Capacitor
• Voltage regulator
• #### 13.  In a rectifier, larger the value of shunt capacitor filter,

• larger the peak-to-peak value of ripple voltage
• larger the peak current in the rectifying diode
• longer the time that current pulse flows through the diode
• smaller the dc voltage across the load

• 0 to π
• α to π
• π+α to 2π
• π to 2π+α
• #### 15.  Q1. A Triac has three terminals viz ……………… None of the above

• Drain, source, gate
• Two main terminal and a gate terminal
• Cathode, anode, gate
• Cathode, anode, emitter
• #### 16.  Apakah kelebihan litar penerus terkawal sepenuhnya?

• Hasilkan keluaran yg bolehubah
• Hasilkan gelombang yang baik
• Hasilkan voltan keluaran yang sama nilainya
• Hasilkan kawalan stabil

• α > 30°
• Vm sinα > E
• Vm sinα < E
• α < 30°