Download AS lab 4

ECE 101
AS
Exploring Electrical Engineering
LAB 4
PSU
ECE 101 Lab 4
Take 3 resistors of different sizes, with resistance ratios of about 1:10:100. Then measure for
some fixed, small, constant voltage the voltage division (AKA voltage drops) across the 3
resistors, when all 3 are in series. Do the same, with all 3 in parallel, and measure the 3 divided
currents. Summarize findings and conclude in a brief report. For the measurements of A and V
you may use V-meters and A-meters, or an oscilloscope.
Objectives:
i)
To conduct experiment to measure voltage across 3 resistors having resistance
values in the ratio of 1:10:100. in a series circuit.
ii)
To conduct experiment to measure 3 branch currents in a parallel circuit having 3
parallel resistors having value of 1: 10: 100
iii)
To write a summary report on the above two circuits and to explain the voltage and
current distribution in the series and parallel circuit.
Equipment:
i) 3 resistors having different resistance values (R1, R2, and R3) in the ratio of 1: 10:100.
ii) Variable DC Voltage source
iii) DC Ammeters in mA range and Voltmeters (0-10volts) range or Multimeter.
Procedure:
i) Connect 3 resistors R1, R2 and R3 having different values in the ratio 1:10:100 (for example
100 Ohms, 1000 Ohms and 10,000 ohms) respectively in series with a DC power supply and an
ammeter as shown in figure 1.
ii) Connect DC voltmeter (0 to 10 volts range) across each resistors
iii) Switch on the DC power supply and apply fixed small voltage from variable DC power
supply, and note down the current value in the ammeter and voltages across each resistor by
voltmeter.
iv) Tabulate the readings in the table T1.1 as given below.
v) Repeat the step iii) and iv) for other two or more fixed small voltages.
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ECE 101
AS
Exploring Electrical Engineering
LAB 4
PSU
figure 1
Sl.No
Applied DC
voltage
In volts
Ammeter
reading
in mA
Volt meter
Volt
reading
meter
across R1
reading
in volts
across R2
in volts
Volt meter
reading
across R3
in volts
Remark
1
2
3
4
Table T 1.1
Procedure:
i) Connect 3 resistors R1, R2 and R3 having different values in the ratio 1:10:100 (for example
100 Ohms, 1000 Ohms and 10,000 ohms) respectively in parallel with a DC power supply,
voltmeter and ammeters as shown in figure 2.
ii) Connect DC ammeters (of few mA range) in 3 branches as shown in figure. Switch on the
DC supply voltage.
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ECE 101
AS
Exploring Electrical Engineering
LAB 4
PSU
Figure 2
iii) Apply fixed small voltage from variable DC power supply, and note down the current value
in the ammeters and voltage across the resistors by voltmeter.
iv) Tabulate the readings in the table T 1.2 as given below.
v) Repeat the step iii) and iv) for other two or more fixed small increased voltages.
Sl.No
Applied DC
voltage
In volts
Volt meter
reading
in Volts
measured
across
resistors.
Ammeter
meter
reading in
series with
R1
in mA
Ammeter
meter
reading in
series
with R2
in mA
Ammeter
meter
reading in
series with
R3
in mA
Remark
1
2
3
4
Table T 1.2
vi) Write a brief report on your observation on voltage and current distribution in series and
parallel circuits.
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