Electrical Engineering Experiments: Circuit Laws and Diode Characteristics, Summaries of Electrical and Electronics Engineering

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PO 7 : Ethics: Apply ethical principles and commit to professional ethics, human values, diversity and inclusion; adhere to national & international laws. PO 8 : Individual and Collaborative Teamwork: Function effectively as an individual, and as a member or leader in diverse/multi-disciplinary teams. PO 9 : Communication: Communicate effectively and inclusively within the engineering community and society at large, such as being able to comprehend and write effective reports and design documentation, make effective presentations considering cultural, language, and learning differences. PO1 0 : Project Management and Finance: Apply knowledge and understanding of engineering management principles and economic decision-making and apply these to one’s own work, as a member and leader in a team, and to manage projects in multidisciplinary environments. PO1 1 : Life-Long Learning: Recognize the need for and have the preparation and ability for i) independent and life-long learning ii) adaptability to new and emerging technologies and iii) critical thinking in the broadest context of technological change.

PROGRAM EDUCATIONAL OBJECTIVES

(PEOs)

PEO1 (^) Graduates will excel in providing optimal solutions to real-time engineering problems in Electrical and Electronics Engineering and multidisciplinary fields. PEO2 (^) Graduates will develop the abilities for lifelong learning and pursue higher education in the core area. PEO3 (^) Graduates will exhibit entrepreneurial qualities with a strong commitment to professional integrity. PEO4 (^) Graduates will adapt good human values and professional ethics to serve society through their core expertise.

PROGRAM SPECIFIC OUTCOMES (PSOs)

On successful completion of the Program, the students shall be able to: PSO Solve complex engineering problems in Power System, Analog and Digital electronics, electrical machines, renewable energy systems, Embedded Systems and Electric vehicles, and Industrial Automation using state-of-the-art techniques. PSO Use modern engineering hardware and software tools in electrical and electronics engineering to adapt in multi-disciplinary area and engage in life-long learning.

PSO Provide engineering solutions considering societal and environmental implications, professional ethics, and communicate effectively with diverse stakeholders.

COURSE OUTCOMES

On successful completion of the course students shall be able to: CO1. Verify basic electrical laws such as Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL) for given electrical circuit. CO2. Calculate current, voltage, power, impedance, and power factor in AC RL, RC, and RLC circuits using experimental setups. CO3. Determine efficiency and loading effects in single-phase transformers through load and no-load conditions. CO4. Plot the performance characteristics of a DC shunt motor by conducting a suitable experiment. CO5. Plot the characteristics of PN junction diodes, Zener diodes, and NPN transistors under various biasing conditions. CO6. Interpret output waveforms, ripple factor, and voltage gain to assess the performance of rectifier and amplifier circuits.

EXPERIMENT – 01

Verification of Kirchhoff’s Voltage and Current Laws

for a DC circuit

Aim: To verify Kirchhoff’s Voltage Law and Kirchhoff’s Current Law theoretically and practically Apparatus Required: Sl. No. Name of the Equipment Quantity 1 Breadboard 1 2 Regulated power supply 1 3 Voltmeter 4 4 Ammeter 3 5 Resistors 3 6 Connecting wires As required Theory: A single equivalent resistance (Req) can be found when two or more resistors are connected together in either series of parallel or combinations of both, and that these circuits obey Ohm’s Law. However, sometimes in complex circuits such as bridge or T networks, we cannot simply use Ohm’s Law alone to find the voltages or currents circulating within the circuit. For these types of calculations, we need certain rules which allow us to obtain the circuit equations and for this we can use Kirchhoff’s Circuit Law. Kirchhoff’s Voltage Law: It states that “In any closed loop network, the total voltage around the loop is equal to the sum of all the voltage drops within the same loop” which is also equal to zero. In other words, the algebraic sum of all voltages within a loop must be equal to zero. This is known as the Conservation of Energy.

Kirchhoff’s Current Law: It states that “Total current entering a junction or node is exactly equal to the current leaving the node as it has no other place to go except to leave, as no charge is lost within a node”. In other words, the algebraic sum of all currents entering and leaving a node must be equal to zero. This is known as the Conservation of Charge. Circuit Diagram: Verification of Kirchhoff’s Voltage Law Verification of Kirchhoff’s Current Law Procedure:

1. To verify KVL, connections are made as shown in figure 1.
2. Supply is given to the circuit and the readings of the voltmeters are noted down.
3. Kirchhoff’s Voltage Law can be verified by Vs = V 1 + V 2 + V 3
4. To verify KCL, connections are made as shown in figure 2.

EXPERIMENT – 02

Verification of Impedance and Current of Series RL,

RC and RLC circuits

Aim: To calculate and verify the impedance and current of RL, RC and RLC series circuits. Apparatus Required: Sl. No. Name of the Equipment Quantity 1 Function generator 1 2 Decade Resistance Box 1 3 Decade Capacitance Box 1 4 Decade Inductance Box 1 5 Oscilloscope 1 6 Voltmeter 1 7 Ammeter 1 8 CRO probes 2 9 Connecting wires As required Theory: RL Circuit: When a resistor is connected with an inductor in series, and this combination is connected across a power source, then the resulting circuit is known as series RL circuit. In RL circuit, the energy is consumed in two phenomena viz. dissipated as heat by the resistor (R) and stored in magnetic field of the inductor (L). In a resistor, the voltage and current are in phase, while in an inductor, the voltage and current are not in phase. The voltage leads the current by 90°, meaning the voltage reaches its maximum and zero levels 90 degrees before the current. The impedance of series RL Circuit is nothing but the combine effect of resistance (R) and inductive reactance (XL) of the circuit as a whole.

RC Circuit: When a resistor is connected with a capacitor in series, and this combination is connected across a power source, then the resulting circuit is known as series RC circuit. A typical series RC circuit is shown in Fig. 2(a). In RC circuit, the energy is consumed in two phenomena viz. dissipated as heat by the resistor (R) and stored in electric field of the capacitor (C). In a resistor, the voltage and current are in phase, while in a capacitor, the voltage and current are not in phase. The voltage lags the current by 90°, meaning the voltage reaches its maximum and zero levels 90 degrees after the current. The impedance of series RC Circuit is nothing but the combine effect of resistance (R) and capacitance reactance (XC) of the circuit as a whole. Circuit Diagram: Procedure:

1. Connections are made as per the circuit diagram
2. Connect the CRO probe at point A to get voltage waveform and at B to get the current waveform.
3. Adjust vertical deflection of each channel such that the waveform fills the whole screen.
4. Adjust the sweep rate and the horizontal position control until one half cycle of the waveform spans 9 divisions on the scope’s scale.
5. Since one half cycle covers 9 divisions, it means each major division on the scope represents 200.
6. Since each major division consists of 5 smaller divisions, each smaller division represents 20/5 = 40.
7. Phase difference between two waveforms is determined by simply counting the number of small divisions between corresponding points on the 2 waveforms.
8. Phase Angle φ= (no. of divisions) * (degree / divisions).
9. Power Factor is given by cosφ

Level 2: Repeat the same for an RLC circuit Circuit Diagram: Observation Table: Series RLC Circuit Practical Theoretical Impedance Power Factor Theoretical Calculations: Result/Inference:

EXPERIMENT – 03

Calculation of Power and Power Factor of an AC circuit

Aim: To measure the power and calculate the power factor in the given lamp load. Apparatus Required: Sl. No. Name of the Equipment Quantity 1 Voltmeter 1 2 Ammeter 1 3 Wattmeter 1 4 Autotransformer 1 5 Lamp load 1 6 Connecting wires As required Circuit Diagram: Procedure

1. Make the connections as shown in figure
2. Ensure that lamp switches are in the OFF position.
3. Switch ON the power supply.
4. Slowly vary the autotransformer and apply 220V to the circuit.
5. Turn on the lamp load switches in steps and note down the ammeter, voltmeter and wattmeter readings.
6. Note down the wattmeter constant.
7. Calculate the power factor using the formula Cosφ = W/V*I

EXPERIMENT – 04

Study the V-I characteristics for the PN junction diode

Aim: To study the Forward and Reverse V-I characteristics of a PN Junction Diode and determine the cut-in voltage. Apparatus Required: Sl. No. Name of the Equipment Quantity 1 Breadboard 1 2 Diode (1N4007) 1 3 Power supply 1 4 Ammeter 1 5 Voltmeter 1 6 Resistors 1 7 Connecting wires As required Theory: The PN junction is a junction formed together by P-type semiconductor and N-type semiconductor material. The region where both N-type and P-type material are joined together is called junction, also known as the boundary of the semiconductor. The majority charge carriers in the P region are holes, while majority charge carriers in N-region are electrons. When the junction is formed, the holes present in the P region are diffuse into the N-region, leaving behind the negative charge in the P region which then recombines with electrons, resulting negatively charged ions in the P-region. Similarly, electrons present at the N-region diffuse into the P-region leaving behind the positive charge in the N-region and recombine with the holes, creating positively charged ions in the N-region. As the junction is formed each region of silicon crystal becomes depleted from major charge carriers around the junction. This region is known as depletion or space charge region. The width of this region highly affects the current flowing between the junctions. Under normal conduction, when there is no voltage applied across the PN junction, the junction is said to have in an equilibrium state. The potential difference formed in that state is called built-in potential which is 0.7 V for silicon semiconductors and 0.3 V for germanium semiconductors. Forward Bias: If a positive voltage is applied at the P-region and a negative voltage is applied at the N-region, it makes the junction forward biased. With forward bias voltage, the electrons

present in the N-region will push toward the P-region, similarly, holes in the P-region will continue to diffuse into the N-region as long as the forward bias voltage is applied across the junction. So, we can conclude that, when PN junction is forward biased, both electrons and holes will push towards the junction, the depletion region will be very thin, resistance is low, and there is a significant amount of current flowing across the junction. Reverse Bias: If PN junction is biased in such a way, its P-side is connected with a negative voltage while N-side is connected with a positive voltage, it will constitute a reverse biased condition. When reverse bias voltage increases, it will increase the depletion region, which stops the current flow between the junction and exhibits maximum resistance at that point. In this condition, PN junction behaves as an insulator. Characteristics : Following figure shows the V vs I characteristic curve of a silicon diode. We can see from the curve when the forward bias voltage is increased, it will increase the current flowing through the diode. Forward bias voltage above 0.7 V is required to allow the diode starts conducting. Under reverse bias condition, a diode will show a different behavior and exhibits no or very little current flowing through the diode. The small current flowing under reverse bias condition is known as leakage current.

Observation Table: Forward Bias Sl. No. Applied Voltage (V) Diode voltage (V) Diode current (mA) 1 0 2 0. 3 0. 4 0. 5 0. 6 0. 7 0. 8 0. 9 0. 10 0. 11 1. 12 2. 13 3. 14 4. 15 5. Reverse Bias Sl. No. Applied Voltage (V) Diode voltage (V) Diode current (mA) 1 0 2 5 3 10 4 15 5 20 6 25 7 30

Theoretical Calculations: Cut-in Voltage from forward bias V-I characteristics: _____________ Static forward resistance: 𝑅𝑑𝑐 = 𝑉𝑓 𝐼𝑓

Dynamic forward resistance: 𝑟𝑎𝑐 = Δ𝑉𝑓 Δ𝐼𝑓

Static reverse resistance: 𝑅𝑑𝑐 = 𝑉𝑟 𝐼𝑟

Dynamic reverse resistance: 𝑟𝑎𝑐 = Δ𝑉𝑟 Δ𝐼𝑟

Result/Inference: