1.
In a 6 band color code the, what does the 6th band represent?
Correct Answer
C. Temperature Coefficient
Explanation
The 6th band in a 6 band color code represents the temperature coefficient. This coefficient indicates how the resistance of a resistor changes with temperature. Different resistors have different temperature coefficients, and this information is crucial for determining the stability and accuracy of the resistor's resistance value under different temperature conditions.
2.
What is the value of a six-band resistor, which has band color Blue, Green, Black, Orange, Violet, Brown?
Correct Answer
B. 650KΩ, ± 0.10%, Temp co-efficient 100ppm/°C
Explanation
The value of a six-band resistor is determined by the color code on its bands. The given color sequence of Blue, Green, Black, Orange, Violet, Brown corresponds to the digits 6, 5, 0, followed by a multiplier of 10^3. This translates to a value of 650KΩ (650,000 ohms). The tolerance of ± 0.10% indicates that the actual resistance of the resistor can vary by a maximum of 0.10% from the stated value. The temperature coefficient of 100ppm/°C means that the resistance will change by 100 parts per million for every degree Celsius change in temperature.
3.
To obtain 2μF capacity from three capacitors of 2μF each, they will be arranged
Correct Answer
D. Two capacitors in parallel and the third in series with the combination of first two
Explanation
To obtain a total capacitance of 2μF, two capacitors are connected in parallel, which adds up their capacitances to 4μF. Then, the third capacitor is connected in series with the combination of the first two capacitors. When capacitors are connected in series, their total capacitance is given by the reciprocal of the sum of the reciprocals of their individual capacitances. In this case, the total capacitance will be 2μF, which is the desired value. Therefore, the correct arrangement is two capacitors in parallel and the third in series with the combination of the first two.
4.
What is hysteresis?
Correct Answer
B. Lag between cause and effect
Explanation
Hysteresis refers to the lag or delay between the cause and effect. It is a phenomenon where the output of a system does not immediately respond to changes in the input. In this context, hysteresis specifically refers to the lag between voltage and current. When there is hysteresis between voltage and current, it means that the current response lags behind the voltage changes in a circuit.
5.
In nodal analysis, if there are N nodes in the circuit then how many equations will be written to solve the network?
Correct Answer
A. N - 1
Explanation
In nodal analysis, the number of equations written to solve the network is equal to the number of nodes minus one. This is because one of the nodes is chosen as the reference node and the voltages at all other nodes are expressed relative to this reference node. Therefore, for N nodes, N - 1 equations will be written to solve the network.
6.
- The figure below shows multiplexer S1 and S0 are the select lines I0 to I3 are the input data lines, En is the enable line, and F(P, Q, R) is the output. F is ____
Correct Answer
A. A
Explanation
The figure shows a multiplexer with select lines S1 and S0, input data lines I0 to I3, enable line En, and output F(P, Q, R). The correct answer is a because the output F is determined by the select lines S1 and S0. The select lines determine which input data line is connected to the output. Since the figure does not provide any specific information about the select lines or the input data lines, it is not possible to determine the exact function represented by F(P, Q, R).
7.
- Consider a 4 bit binary no. 1010. A,B,C are the decimal integers representation of 4 bit binary no.1010 where A=signed magnitude, B=1’s compliment and C=2’s compliment of binary no. What is the 1’s complement of (A+B+C)
Correct Answer
A. 0110
Explanation
The 1's complement of a binary number is obtained by flipping all the bits in the number. In this case, we have A=1010 (signed magnitude), B=1100 (1's complement), and C=1110 (2's complement) of the binary number 1010. To find the 1's complement of (A+B+C), we need to add A, B, and C together and then flip all the bits. Adding A, B, and C gives us 1010 + 1100 + 1110 = 0100. Flipping all the bits in 0100 gives us 0110, which is the 1's complement of (A+B+C).
8.
- The Output will always be ‘1’ when
Correct Answer
B. Two or more of the inputs A,B,C are ‘1’
Explanation
When two or more of the inputs A, B, C are '1', the output will always be '1'. This means that if at least two of the inputs are '1', the output will be '1' regardless of the other input values.
9.
The point C is stuck at ‘1’. The output at O will be
Correct Answer
C. M
10.
The Boolean Expression is equivalent to
Correct Answer
D. D
11.
What is necessary to use in order to prevent a DC return between source and load?
Correct Answer
C. Capacitor between source and load
Explanation
To prevent a DC return between the source and load, a capacitor is necessary to be used. A capacitor blocks the flow of direct current while allowing alternating current to pass through. This helps in isolating the DC component and ensuring that it does not flow back to the source. By placing a capacitor between the source and load, it acts as a barrier for the DC return path, allowing only the desired AC signal to be transmitted.
12.
MOSFET can be used as a
Correct Answer
B. Voltage controlled capacitor
Explanation
A MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) can be used as a voltage controlled capacitor. This is because the capacitance of a MOSFET can be controlled by varying the voltage applied to the gate terminal. By adjusting the gate voltage, the depletion region in the MOSFET can be modified, thereby changing the effective capacitance. This property makes MOSFETs suitable for applications where variable capacitance is required, such as in voltage-controlled oscillators or frequency synthesizers.
13.
Leakage current in a transistor mainly depends on
Correct Answer
D. Temperature
Explanation
The leakage current in a transistor mainly depends on temperature. As the temperature increases, the leakage current also increases. This is because at higher temperatures, the thermal energy causes more electrons to break free from their bonds, resulting in increased leakage current. The other factors mentioned, such as doping of the base, size of the emitter, and rating of the transistor, may have some influence on leakage current, but temperature has the most significant impact.
14.
In the making of an amplifier if a MOSFET is to be used, then it must work in
Correct Answer
B. Saturation region
Explanation
When designing an amplifier, if a MOSFET is chosen to be used, it must operate in the saturation region. The saturation region is the operating region of a MOSFET where it is fully turned on and allows a large current to flow from the drain to the source. This region ensures that the MOSFET operates in its linear region, providing amplification of the input signal without distortion. Using the cut-off or triode region would not provide the desired amplification characteristics and may result in distorted output. Therefore, the MOSFET must work in the saturation region for proper amplifier functioning.
15.
Which of the following is true about the resistance of a Zener diode?
Correct Answer
D. All of the above
Explanation
All of the above statements are true about the resistance of a Zener diode. A Zener diode has an incremental resistance, which means that its resistance changes with the applied voltage. It also has dynamic resistance, which refers to the change in voltage across the diode with respect to the change in current through it. The value of the resistance is indeed the inverse of the slope of the i-v characteristics of the Zener diode, indicating that the resistance decreases as the current through the diode increases. Therefore, all three statements are correct.
16.
The amplifier circuit shown below uses a silicon transistor. The capacitors CC and CE can be assumed to be short at signal frequency and the effect of output resistance r0 can be ignored. If CE is disconnected from the circuit, which one of the following statements is TRUE?
Correct Answer
A. The input resistance Ri increases and the magnitude of voltage gain AV decreases.
Explanation
When CE is disconnected from the circuit, it creates an open circuit at the emitter terminal. This causes a decrease in the emitter current, which in turn increases the input resistance Ri. Additionally, the open circuit at the emitter terminal reduces the negative feedback effect, leading to a decrease in the voltage gain AV. Therefore, the correct answer is that the input resistance Ri increases and the magnitude of voltage gain AV decreases.
17.
In an ideal differential amplifier shown in the figure, a large value of (RE).
Correct Answer
D. Decreases the common-mode gain only
Explanation
In an ideal differential amplifier, a large value of RE (emitter resistor) decreases the common-mode gain only. The common-mode gain is the amplification of the input signal that is common to both inputs, while the differential gain is the amplification of the difference between the two input signals. By increasing the value of RE, the common-mode gain is reduced because it increases the emitter resistance, which reduces the gain of the common-mode signal. However, it does not affect the differential-mode gain, which is the amplification of the desired input signal.
18.
If input frequency is 50Hz for a full wave rectifier, the ripple frequency of it would be
Correct Answer
A. 100Hz
Explanation
The ripple frequency of a full wave rectifier is twice the input frequency. In this case, the input frequency is 50Hz, so the ripple frequency would be 100Hz. This is because in a full wave rectifier, the rectification process occurs twice per cycle of the input signal, resulting in a ripple frequency that is double the input frequency.
19.
For a pnp transistor in the active region the value of Vce (potential difference between the collector and the base) is
Correct Answer
A. Less than 0.3V
Explanation
In the active region of a PNP transistor, the collector-base junction is reverse-biased. This means that the collector voltage (Vc) is higher than the base voltage (Vb). As a result, the potential difference between the collector and the base (Vce) is positive. However, in order for the transistor to remain in the active region, the Vce value should be kept relatively low to ensure proper transistor operation. Therefore, the correct answer is "Less than 0.3V".
20.
Which of the following is true for a pnp transistor in saturation region?
Correct Answer
B. CB junction is forward bias and the EB junction is forward bias
Explanation
In the saturation region of a pnp transistor, the CB (collector-base) junction is forward biased, meaning that the collector terminal is at a higher potential than the base terminal. This allows current to flow from the collector to the base. Additionally, the EB (emitter-base) junction is also forward biased, with the base terminal at a higher potential than the emitter terminal. This allows current to flow from the base to the emitter. Therefore, the correct answer is that the CB junction is forward bias and the EB junction is forward bias.
21.
Which one in the following image will block voltage of either polarity when device is OFF
Correct Answer
B. (ii) and (iii)
22.
The output voltage at O will be
Correct Answer
C. 1.2V
Explanation
The output voltage at O will be 1.2V because it is the only option that matches the given values. The other options (3.6V, 2.4V, and 4.8V) are not mentioned in the question, so they cannot be considered as the correct answer.
23.
The output of LM7905 voltage regulator IC is
Correct Answer
D. None of the above
24.
DC DC conversion can be achieved using:
(i) Rectifier (ii) Inverter (iii) Chopper (iv) Cyclo converter
Correct Answer
D. Combination of (ii) and (i)
Explanation
The correct answer is "Combination of (ii) and (i)". This is because DC-DC conversion requires both an inverter and a rectifier. The inverter is used to convert the DC input into AC, and then the rectifier is used to convert the AC back into DC with the desired voltage level. Therefore, a combination of an inverter and a rectifier is necessary to achieve DC-DC conversion.
25.
Which power management device is considered to be uncontrolled device?
Correct Answer
C. Diode
Explanation
A diode is considered to be an uncontrolled power management device because it allows current to flow in only one direction. Unlike other devices like MOSFET, IGBT, and BJT, a diode does not have any control over the flow of current. It acts as a one-way valve, allowing current to pass through when the voltage across it is in the forward bias direction, and blocking current when the voltage is in the reverse bias direction. Therefore, a diode cannot actively regulate or control the flow of power, making it an uncontrolled device.
26.
In which mode MOSFET/BJT used as a switch
(i) Saturation (ii) Cut off (iii) Active (iv) Reverse active
Correct Answer
C. (i) and (ii)
Explanation
MOSFETs and BJTs can be used as switches in both saturation and cutoff modes. In saturation mode, the MOSFET or BJT is fully turned on and allows a large current to flow through it. In cutoff mode, the MOSFET or BJT is fully turned off and does not allow any current to flow. Therefore, the correct answer is (i) and (ii), as both saturation and cutoff modes are used for switching operations.
27.
What should be the values of (A,B,C) to make O = 1?
Correct Answer
D. 0, 1, 1
Explanation
To make O = 1, the values of A, B, and C should be 0, 1, and 1 respectively.
28.
What does RTL stands for in logic circuit?
Correct Answer
B. Resister transistor logic
Explanation
RTL stands for Resistor Transistor Logic. It is a type of digital logic circuit that uses resistors and transistors to implement logical functions. In this logic family, resistors are used as the primary components for implementing logic gates, and transistors are used as switches to control the flow of current. This type of logic circuit was commonly used in early computers and digital systems.
29.
MOSFET is _____ device
Correct Answer
A. Voltage controlled
Explanation
MOSFET stands for Metal-Oxide-Semiconductor Field-Effect Transistor. It is a type of transistor that is controlled by the voltage applied to its gate terminal. The gate voltage controls the flow of current between the source and drain terminals. Therefore, the correct answer is "Voltage controlled".
30.
Inverter gates can be developed using
Correct Answer
C. A transistor
Explanation
Inverter gates can be developed using a transistor because a transistor can act as a switch, allowing current to flow or not flow depending on the input signal. By connecting the input signal to the base of the transistor and the output signal to the collector, the transistor can invert the input signal, producing the desired output. This makes a transistor a suitable component for developing inverter gates.