1. verification of ohms law - archanakc.files.wordpress.com€¦ · web view15 volts dc / 2...

BASIC ELECTRICAL ENGINEERING LAB

1. VERIFICATION OF OHMS LAW

1.1 OBJECTIVE To verify The Ohms Law

1.2 RESOURCES

S. No. Name of the Equipment Type Range Qty01 Voltmeters DC Digital (0-20)V 0102 Ammeters DC Digital (0-2)A 0103 Resisters - -04 DC Power Supply Source - 15 Volts DC / 2 amp -

1.3 CIRCUIT DIAGRAM

1.4 PROCEDURE1. Give the connections as per the circuit diagram.

2. Set a particular value in DC Power source.

3. Note down the corresponding ammeter reading

4. Repeat the same for different Voltage and verify the ohm’s law V=IR

1.5 TABULAR COLUMN

Sl. No. VoltageV

CurrentA

0102030405

1.6 MODEL GRAPH

1.7 RESULTHence Ohms Law is Verified.

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1.8 PRE LAB QUESTIONS1. What is current?

2. What is voltage?

3. Define charge.

4. Define power.

5. What is the resistance?

6. What is ohm’s law?

7.

1.9 POST LAB QUESTIONS

1. What do you mean by junction?

2. What is the colour coding of resistors?

3. What are the precautions to be taken while doing the experiment?

4. What is the range of ammeters and voltmeters you used in this experiment?

5. What are the limitations of ohm’s law?

6. What is the condition of ohm’s law?

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2. Verification of KVL and KCL

2.1 OBJECTIVETo verify The KVL & KCL For The Given Circuits.

2.2 RESOURCESSl. No. Apparatus Type Range Quantity

01 Voltmeters DC Digital (0-20)V 0302 Ammeters DC Digital (0-2)A 0303 Resisters --- ---04 DC Power Supply source ----- 15 Volts DC / 1 amp ------05 Connecting Wires ----- Required

2.3 CIRCUIT DIAGRAMCIRCUIT DIAGRAM FOR KCL :

CIRCUIT DIAGRAM FOR KVL:

2.4 PROCEDURE KCL

1. Give the connections as per the circuit diagram.


3. Note down the corresponding ammeter reading

4. Repeat the same for different voltages

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KVL:

1. Give the connections as per the circuit diagram.


3. Note all the voltage reading

4. Repeat the same for different voltages

2.5 TABULAR COLUMN

KCL :

Sl. No. VoltageE

Current I1 = I2 + I3I1 I2 I3

Volts A A A A01020304

KVL :

Sl. No. Voltage E Voltage KVLV1 V2 E1 = V1 + V2

(E1) Volts V V01020304

2.6 RESULTHence kcl and kvl are verified theoretically and practically.

2.7 PRE LAB VIVA QUESTIONS1. What is current?

2. What is voltage?

3. What is resistance?

4. What is ohm’s law?

5. What is KCL and KVL?

2.8 POST LAB VIVA QUESTIONS

1. What do you mean by junction?

2. What directions should be assumed for KCL?

3. What are the positive and negative signs in KVL?

4. What is the colour coding of resistors?

5. What are the precautions to be taken while doing the experiment?

6. What is the range of ammeters and voltmeters you used in this experiment?

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EXPERIMENT – 3: TRANSIENT RESPONSE OF SERIES RL AND RC CIRCUITS USING DC EXCITATION

3.1 OBJECTIVEStudy the transient response of a series RC circuit and understand the time constant

concept with DC Power Supply.

3.2 RESOURCES

Sl.No. Apparatus Range Quantity

01 Resisters R1, R2 and R3 inKilo ohms 03

02 Inductors L in milli Henrys 0103 Capacitors C in micro farad 0104 DC Power Supply source 15 Volts DC / 1 amp ------05 Connecting Wires ----- Required

06 Digital Storage Oscilloscope (CADO801) 30MHZ 01

3.3 CIRCUIT DIAGRAM RC & RL CIRCUIT :

RC & RL CIRCUIT

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3.4 PROCEDUREFor RC circuit:

1. Make sure that the toggle switch connected across the DC Supply is in downward position.

2. Connect +5V DC Power Supply to the input of RC Circuit i.e., connect +5V terminal to terminal 1 and Gnd terminal to terminal 2.

3. Connect the mains cord to the Trainer and switch ‘On’ the mains supply.4. Connect terminal 3 with resistance R1 (terminal 4).5. Now switch ‘On’ the power switch of the trainer.

6. Connect DSO across capacitor i.e. across terminal 7 and terminal 8. Keep DSO at 10 seconds or more Time Base.

7. Switch the toggle switch in upward direction so that DC Supply will connect to the RC circuit.

8. Observe the transient response (exponentially rising) on DSO till the steady state (+5V DC level) is achieved i.e. for 50 seconds (for case R=10 K and C= 1000 μF).

9. Now switch the toggle switch in downward direction so that resistor, R will short with capacitor, C.

10. Now observe the response (exponentially decaying) till it reaches reference level of DSO. Now immediately press RUN/STOP Switch of DSO to hold the response shown on the DSO screen.

11. Repeat the procedure for the different resistors provided, observe and analyze the result.

CALCULATIONS: RC Circuit1. Theoretically,

Time Constant, TC = R C = ……………..where,

R1 = 10 K, C = 1000 μF.R2 = 20 K, C = 1000 μF.R3 = 3.3 K, C = 1000 μF.

Practically (on DSO screen),In the charging circuit, Time Constant is the time by which the capacitor attains the 63.2% of steady state voltage or final value (in our case, +5 V).

Time Constant or Time required to rise to 63.2% of 5 V (i.e. 3.16 V) =…………In the discharging circuit, Time Constant is time by which the capacitor discharges to 36.8% of its initial steady state voltage (in our case, +5 V).

Time Constant or Time required to decay to 36.8% of 5V (i.e. 1.84 V) = ………….

2. Similarly, 2TC is the time required to achieve 86.5% of final or initial value of voltage (i.e. 4.3V).

Practically, 2TC = ……….Theoretically, 2TC =……...

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3. After 5TC, the voltage reaches it’s final value which is also called steady state response (i.e. 5V).Practically, 5TC = ……….Theoretically, 5TC =……...PROCEDURE: (For RL circuit)

1. Make sure that the toggle switch connected across the DC Supply is in downward position.

2. Connect +5 V DC Power Supply to the input of RL Circuit i.e. connect +5 V terminal to terminal 1 and Gnd terminal to terminal 2.

3. Connect the mains cord to the Trainer and switch ‘On’ the mains supply.4. Now switch ‘On’ the power switch of the trainer.5. Connect DSO across inductor i.e. across terminal 7 and terminal 8. Keep DSO at 200 μs or 500 μs

Time Base .

6. Observe the transient response switching the toggle switch in upward and downward direction continuously. Now immediately press RUN/STOP Switch of DSO to hold the response shown on the DSO screen.

7. Select the waveform with appropriate peak and observe the time constant on DSO.

4. Theoretically,Time Constant, TC = R C = ……………..where,

L = 800 mH, R1 = 1 KL = 800 mH, R2 = 2 KL = 800 mH, R3 = 3.3 K

Practically (on DSO screen),In the charging circuit, One Time Constant is the time by which the inductor attains the 36.8% of maximum voltage (in our case, +5 V).

Time Constant or Time required to decay to 36.8% of 5 V (i.e. 1.84 V) = ………….

3.5 RESULTTransients analysis of RL and RC are verified.

3.6 PRE LAB QUESTIONS 1. Define Transient and classify2. Deduce the time constant for simple RL series circuit. 3. Deduce the time constant for simple RC series circuit. 4. How will you design the values of L & C in a transient circuit?

3.7 POST LAB QUESTIONS 1. Why it is necessary to discharge the capacitor every time you want to record another

transient voltage across the capacitor?

2. If the capacitor remains charged, what would you expect to see across the capacitor when you re-close the switch to try to record another transient?

3. Give the expression for energy stored in the capacitor?

4. Draw the discharge of capacitor voltage with time in RC circuit?

5. What do you understand from the value of time constants (RL, RC)?

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4.TRANSIENT RESPONSE OF SERIES RLC CIRCUIT USING DC EXCITATION

4.1 OBJECTIVEStudy the transient response of a series RLC circuit and understand the time constant

concept with DC Power Supply.

Study the transient response of a series RLC circuit with TTL for under-damped, critically damped and over-damped cases.

4.2 RESOURCES

Sl.No. Apparatus Range Quantity

01 Resisters R1, R2 and R3 inKilo ohms 03

02 Inductors L in milli Henrys 0303 Capacitors C in micro farad 0104 DC Power Supply source 15 Volts DC / 1 amp ------05 Connecting Wires ----- Required

06 Digital Storage Oscilloscope (CADO801) 30MHZ 01

4.3 CIRCUIT DIAGRAM RLC CIRCUIT

RLC CIRCUIT

4.4 PROCEDURE RLC circuit

1. Connect square wave (TTL) to the input of RLC circuit i.e. connect TTL signal terminal to terminal 1 and Gnd terminal to terminal 2. Square Wave (TTL) is just like manual switching as it automatically switches on and off.

2. Connect the mains cord to the Trainer and switch ‘On’ the mains supply.3. Connect terminal 3 with resistance R1 (terminal 4).4. Now switch ‘On’ the power switch of the trainer.5. Connect DSO across capacitor i.e. across terminal 7 and terminal 8. Keep DSO at 10 seconds or

more Time Base.

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6. Switch the toggle switch in upward direction so that DC Supply will connect to the RC circuit.

7. Observe the transient response (exponentially rising) on DSO till the steady state (+5V DC level) is achieved i.e. for 50 seconds.

8. Now switch the toggle switch in downward direction so that resistor, R will short with capacitor, C.

9. Now observe the response (exponentially decaying) till it reaches reference level of DSO. Now immediately press RUN/STOP Switch of DSO to hold the response shown on the DSO screen.

10. Repeat the procedure for the different resistors provided, observe and analyze the result.

Follow the same procedure for different cases whenC=1000 pF,

= 63 Ω approx.L1 = 10 mH, RL1L2 = 15 mH, RL2 = 97 Ω approx.L3 = 20 mH, RL3 = 133 Ω approx.

4.7 RESULTTransients analysis of RLC is verified.

4.5 PRE LAB QUESTIONS 1. Define Transient and classify 2. Deduce the time constant for simple RL series circuit. 3. Deduce the time constant for simple RC series circuit. 4. How will you design the values of L & C in a transient circuit?

4.6 POST LAB QUESTIONS 1. Why it is necessary to discharge the capacitor every time you want to record another

transient voltage across the capacitor?

2. If the capacitor remains charged, what would you expect to see across the capacitor when you re-close the switch to try to record another transient?

3. Give the expression for energy stored in the capacitor?

4. Draw the discharge of capacitor voltage with time in RC circuit?

5. What do you understand from the value of time constants (RL, RC)?

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5.RESONANCE IN SERIES AND PARALLEL RLC CIRCUITS

5.1 OBJECTIVE

To determine the resonant frequency fo, Bandwidth and quality factor Q, of the given series and parallel RLC circuits.

5.2 CIRCUIT DIAGRAMSeries Resonance

5.3 PROCEDUREResonance in series RLC circuits:

1. Set the signal generator in sine wave mode and the output voltage to 20V peak to peak.

2. Connect the circuit as per fig and vary the frequency of the input signal in steps and note down the corresponding current through the circuit and tabulate the readings.

3. Reduce the frequency to zero and disconnect the circuit and plot the graph by relating dependent and independent variables.

5.4 PRECAUTIONS1. Keep the output voltage of the signal generator in zero volt position.

2. Set the ammeter pointer at zero position.

3. Take the readings without parallax error.

4. Avoid loose connections

5.5 FORMULAS

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5.6 TABULAR COLUMN

Sl. No SERIES RESONANCEFrequency, f (Hz) Current, I(mA)

OBSERVATIONS

Sl. NoSERIES RESONANCE

PARAMETER CIRCUITTheoretical Practical

Resonant Frequency, (fo)Band width

Quality factor

5.7 RESULTResonance of series circuit is verified and resonance frequency, band width and quality

factor are calculated.

5.8 PRE LAB QUESTIONS1. What is Resonance.2. What is the condition for Resonance.3. What are the applications of Resonance.

5.8 POST LAB QUESTION1. What do understood by conducting this test.2. Is resonance condition is justified in this test.

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6.VERIFICATION OF IMPEDANCE AND CURRENT OF RL, RC AND RLC SERIES CIRCUITS

6.1 AIM To verify the Impedance and Current of RL, RC and RLC Series Circuits

6.2 APPARATUS REQUIRED

Sl.No. Apparatus Range Quantity01 Resisters 25 ohms 0102 Inductors 110 milli Henrys 0103 Capacitors 160 micro farad 0104 AC Power Supply source 30 Volts AC / 1 amp ------05 Connecting Wires ----- Required

6.3 CIRCUIT DIAGRAM RL SERIES CIRCUIT

Fig: 1 RL SERIES CIRCUIT

RC SERIES CIRCUIT

Fig: 2 RC SERIES CIRCUIT

RLC SERIES CIRCUIT

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Fig: 3 RLC SERIES CIRCUIT

6.4 PROCEDURE:

A) RL SERIES CIRCUIT:

1. Connect the mains cord to the Trainer and switch ‘On’ the mains supply.2. Make the connections as per fig:1 as shown in above.3. Apply some Voltage using Variac up to 30 Volts in steps wise.4. Note down all parameters (Voltage and Current)5. Tabulate the readings.6. Calculate the Impedance (Z) and Current.

B) RC SERIES CIRCUIT:


C) RLC SERIES CIRCUIT:


OBSERVATION TABLE:

V (Volts) I (Amps) Z (Ohms)RL CircuitRC CircuitRLC Circuit

SAMPLE CALCULATIONS: (RL, RC & RLC Series Circuit)

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6.5.PRE LAB QUESTION

1. What is reactance?2. What is the need of reactance?3. Define impedance.4. What is the phase angle between v & I in rl, rc & rlc circuits?

POST LAB QUESTIONS1. IS the angle same for theoretical and practical?

6.6 RESULT:Impedance for different circuits are calculated.

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7 .MEASUREMENT OF 3-PHASE ACTIVE AND REACTIVE POWER FOR BALANCED LOAD

7.1AIM: To measure the Active and Reactive power for STAR connected balanced loads.

7.2APPARATUS REQUIRED:

Sl.No Equipment name quantity

01 Digital voltmeter (0-500Volts AC) 01

02 Digital ammeter (0-10Amps AC) 01

03 Analog wattmeter (0-500V, 5Amps) 02

04 R-Load bank. (STAR Connected) 01

05 Experiment setup. 01

06 Connecting wires. As Required

10.3 CIRCUIT DIAGRAM: (For STAR connected Loads)

10.4 PROCEDURE: (For Balanced connected Loads)

1. Make the connections as per the circuit diagram.

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2. Connect the supply to the STAR connected load through all meters as per the circuit diagram.

3. Switch ON the MCB.4. Apply Voltage using Three Phase dimmerstat up to 400Volts.5. Note down the Readings of voltmeter, ammeter, and wattmeter.6. Switch OFF the STAR Connected load.

7. 10.5 OBSERVATIONS:8.

S.NO VOLTAGE CURRENT Total Active Power (Reactive Power)(W1+W2) (W1+W2)

1.

2.

3.

9.

10.6 CALCULATIONS:CALCULATIONS:

W1 W2

TAN

3W1 W2 1

3 W W TAN

1 2

W1 W2

Power factor = cos

3 phase

10.7 PRECAUTIONS:

1. Avoid loose/ wrong connections.2. Switch off the supply after doing the experiment.

7.8 PRE LAB QUESTIONS

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1. What is active power and reactive power.2. What is the need of reactive power.3. How will measure the reactive power. 7.9.POST LAB QUESTIONS

1. Draw the power triangle.2. Is any difference in reactive power if capacitive and inductive load is connected individually .3. How can we use reactive power in power system applications.

RESULT: Active and Reactive powers for star connected load are calculated.

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1. verification of ohms law - archanakc.files.wordpress.com€¦ · web view15 volts dc / 2...

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