Bangladesh Power Development Board BPDB questions, all the previous year questions for recruitment test of Sub-assistant or Assistant Engineer post of Electrical

Table of Contents

#### Bangladesh Power Development Board – BPDB Questions Assistant Engineer (AE)-2016

- If the following Wye-Delta system Van= 200<0 and Z1=Z2=Z3=20-40J. Find I2 (a,b.c) phase sequence.

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- In the following 3-phase system load 1 draws 20 KW at 0.7 pf lagging, whereas load 2 draws 30 KVAR at pf 0.6 lagging. What is the overall pf for the two loads combined?

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- Two generators, one grounded through a reactor, and one through a resistor, is connected to a bus through a step-up transformer (Y-Y) to a transmission line. Another generator grounded through a reactor is connected to a bus through a transformer (Wye-Delta) to the opposite end of the transmission line. A load is connected to the bus. Draw a single line diagram of the system.

- An alternator on open circuit generates 360V at 60Hz when the field current is 3.6 A. Neglecting saturation, determine the open circuit e.m.f. when the frequency is 40Hz and the field current is 2.4 A.

- Draw a block diagram of a typical standalone solar home system clearly including each component.

- Find Vout of the following op-amp circuit where Vin = 10V and (+Vsat = 14V and –Vsat =-13V)

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- Determine the state (on or off ) of the Zener diode is the following circuit and Iz and Pz.

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- Implement AND, OR, NOT gate using the universal NAND gate.

- Suppose that, there are three message signals to be sent using TDM. The first two signals both have frequency contents within 10KHz. What is the bit rate of the TDM system when it operates efficiently in terms of bandwidth usage?

- The correlation of a(t) & b(t) at lag toue is integration(-infinity to +infinity) a(t) b(t-toue) dt. Determine the correlation of signal pair at zero lag.

Figure