Laboratory Manual BTY309 Biomedical Circuits and Networks Laboratory
Laboratory Manual BTY309 Biomedical Circuits and Networks Laboratory
Laboratory Manual BTY309 Biomedical Circuits and Networks Laboratory
BTY309
BIOMEDICAL CIRCUITS AND
NETWORKS
LABORATORY
1. Kirchhoff’s Voltage Law states that the algebraic sum of all the voltages around any
Figure 1.1
Applying Kirchhoff’s voltage law to the first and the second loops in the circuit shown
in Figure yields:
2. Kirchhoff’s Current Law states that the algebraic sum of all the currents at any node
is zero.
Applying Kirchhoff’s current law to the first four nodes in the circuit shown in Figure yields
Procedure:
1. Construct the circuit shown in Figure 1.1 using the resistors available in laboratory.
3. Accurately measure all voltages and currents in the circuit using the Digital Multi-Meter
(DMM).
4. Record the measurements in a tabular form containing the measured voltage and
current values.
5. Verify KVL for the loops in the circuit using equations 1a and 1b.
6. Verify KCL for the nodes in the circuit using equations 2a, 2b, 2c and 2d.
Precautions:
5. Supply should not be switched ON until and unless the connections are checked by the
Faculty/Lab Instructor
Learning outcomes:
Experiment No.2
Aim: To verify superposition theorem for the given circuit.
Apparatus Required:
THEORY
Superposition Theorem: The voltage and current response of a linear network to
a number of independent sources is the SUM of the responses obtained by
applying each independent source once with the other independent sources set
equal to ZERO. The idea of superposition rests on the linearity property.
Consider the following figure Fig. 1(a), where we need to find the voltage across 3. For this
case we consider each independent source individually and calculate voltages across 3
accordingly, i.e. VAB and V''AB . The net voltage across the resistor 3 is the algebraic sum of
these two voltages which is same as the voltage across 3 when both the independent sources
work together, i.e. V'AB + V ''AB = V AB .
Current Measurement using Superposition Principle
Consider the following figure Fig. 2(a), where we need to find the current across 3. For this
case we consider each independent source individually and calculate currents across 3
accordingly, i.e. I 'AB and I ''AB . The net current across the resistor 3 is the algebraic sum of
these two currents (including the polarity) which is same as the current across 3 when both the
independent sources work together, i.e. I 'AB + I ''AB = I AB .
Precautions:
1. Experiment must be performed in the presence of instructor/lab technician.
2. Connections must be checked before switching on the circuit.
3. Switch off the supply when not in use.
4. Reading should be taken carefully.
5. All connections should be tight and correct.
Learning Outcomes:
Experiment No.3
Aim: To verify Thevenin’s theorem and to find the full load current for the given circuit.
Apparatus Required:
Figure 3.1
Experiment No.4
Aim: To verify Norton’s theorem for the given circuit.
Apparatus required:
Statement:
Any linear, bilateral, active two terminal network can be replaced by an equivalent current
source (IN) in parallel with Norton’s resistance (RN)
Procedure:
2. Set a particular value in RPS and note down the ammeter readings in
the original circuit.
3. To Find IN: Remove the load resistance and short circuit the terminals.
4. For the same RPS voltage note down the ammeter readings.
5. To Find RN: Remove RPS and short circuit the terminal and remove the load
and note down the resistance across the two terminals.
6. Equivalent Circuit: Set IN and RN and note down the ammeter readings.
Figure 4.1
Circuit 2: To find IN
Figure 4.2
Circuit 3: To find RN
Figure 4.3
Precautions:
1. Voltage control knob of RPS should be kept at minimum position.
2. Current control knob of RPS should be kept at maximum position.
Experiment No.5
Aim: To verify maximum power transfer theorem for the given circuit.
Apparatus Required:
Consider the following circuit, where a voltage source is in series with two resistors RL and
RTH. For maximum power transfer across RL load resistance RL must be equal to the
Thevenin’s resistance RTH.
Figure 5.1
The maximum power across the load resistance is given as:
PROCEDURE:
Circuit – I
1. Connections are given as per the diagram and set a particular voltage in RPS.
2. Vary RL and note down the corresponding ammeter and voltmeter reading.
3. Repeat the procedure for different values of RL & Tabulate it.
4. Calculate the power for each value of RL.
To find VTH:
5. Remove the load, and determine the open circuit voltage using multimeter (VTH)
To find RTH:
6. Remove the load and short circuit the voltage source (RPS).
7. Find the looking back resistance (RTH) using multimeter.
Equivalent Circuit:
8. Set VTH using RPS and RTH using DRB and note down the ammeter reading.
9. Calculate the power delivered to the load (RL = RTH)
10. Verify maximum transfer theorem.
CALCULATION:
Learning Outcome:
Experiment No.6
Aim: To study reciprocity theorem.
Apparatus Required:
Theory: In any linear bilateral network, if a single voltage source Va in branch ‘a’
produces a current Ib in branch ‘b’, then if the voltage source Va is removed and inserted in
branch ‘b’ will produce a current Ib in branch ‘a’. The ratio of response to excitation is same
for the two conditions mentioned above. This is called the reciprocity theorem.
Consider the network shown in figure 6.1 AA’ denotes terminals and BB’ denotes output
terminals. The application of voltage V across AA’ produces current I at BB’. Now if the
position of source and responses are interchanged, by connecting the voltage source across
BB’, the resultant current I will be at terminals AA’. According to Reciprocity theorem, the
ratio of response to excitation is the same in both cases.
Figure 6.1
Procedure:
1. Connection are made as per the circuit diagram shown in figure 6.2.
2. Vary the supply voltage V1 and take the corresponding reading I3 from the ammeter.
3. Find out the ratio R= (V1/I3).
4. Now interchange the position of ammeter and variable voltage supply V1 as shown in
figure 6.3.
5. Vary the supply voltage V1 and take the corresponding reading I3’ from the ammeter.
6. Find out the ratio R’=(V1/I3’)
7. Now check whether R and R’ are same.
Figure 6.2
Figure 6.3
Tables:
Experiment No.7:
Aim: To study the compensation theorem.
Apparatus required:
Theory:
The compensation theorem states that any element in the linear, bilateral network may be
replaced by a voltage source of magnitude equal to the current passing through the element
multiplied by the value of the element provided the currents and voltages in other parts of the
circuit remain unchanged. Consider the circuit shown in figure 7.1. The element R can be
replaced by voltage source V, which is equal to the cuurent I passing through R multiplied by
R as shown below.
Figure 7.1
This theorem is useful in finding the changes in current or voltage when the value of resistance
is changed in the circuit as shown in figure 7.2.
Figure 7.2
Procedure:
1. Connections are made as per the circuit diagram shown in figure 7.3.
2. Set the supply voltage V1= 15V and take the corresponding reading
I3 from the ammeter.
3. Now connect the additional resistor (DRB) as shown in figure 7.4.
4. Now fixing V1 = 15 V and finding out the current I3’ due to extra
resistor DRB where Decade Resistance Box value is changed
correspondingly.
5. Now replace the voltage V1 by compensated voltage V2 as shown in
figure 7.5 and find out the current I3’’ due to compensated voltage
V2.
6. Finally find the ammeter reading I=I3-I3’’.
Figure 7.3
Figure 7.4
Figure 7.5
Tables:
EXPERIMENT NO.8
AIM: Determination of transient response of current in RC and RL circuits with step voltage
input.
APPARATUS REQUIRED:
• Bread board
• Resistors, Inductors, Capacitors
• CRO
• Function generator
• Power supply
• Ammeter
• Voltmeter and connecting wires
THEORY:
Figure 8.1
Figure 8.2
Experiment No.9
AIM: Determination of Z and H parameters (dc only) for a two port resistive network.
APPARATUS REQUIRED:
• Bread board
• Resistors, Inductor, Capacitor
• Power supply
• Ammeter
• Voltmeter and connecting wires
THEORY:
Figure 9.1
Figure 9.2
Figure 9.3
PROCEDURE:
Figure 9.4
Worksheet of the student
DATE OF PERFORMANCE:
AIM:
CALCULATION:
RESULT:
Learning Outcome:
Experiment No.10
PROCEDURE:
Low ‐pass Filter 1. Set up the circuit in figure 10.1 .Channel 1 is observing the incoming signal
and channel 2 is looking at the out coming signal. Make sure you use the same ground point in
your circuit for both channels.
2. Set the Vin to 3.5 volts peak to peak (3.5 Vpp) at 500 Hz.
3. Use the measurement tools on the scope to measure the amplitude and frequency of
the incoming signal and outgoing signal.
4. Record the data for 10 points from 500 Hz to 10,000 Hz
5. Graph the results of Vout vs. frequency
6. Calculate the cutoff frequency and compare
Figure 10.1
HIGH PASS FILTER:
1. Build the circuit in figure 10.2.
2. Repeat the above procedure for the high pass filter and find its cut-off frequency from
m graph and calculation.
Figure 10.2