Discuss about various types of Law (EEE)

2. Topic
Various Types Of Law

3. German physicist who experimentally
determined that the if the voltage
across a resistor is increased, the
current through the resistor will
increase.
Ideas were published in 1827, but
they were rejected by his peers. He
lived in poverty for several years
before taking a teaching position.
Called the Mozart of electricity.

4. Ohm's Law
Ohm's Law deals with the relationship between voltage
and current in an ideal conductor. This relationship states
that: The potential difference (voltage) across an ideal
conductor is proportional to the current through it.
The constant of proportionality is called the
"resistance", R.

5. V = I * R
 For a constant resistance, if the current
increases, the voltage increases at the same
rate
I = V / R
For a constant resistance, if the voltage
increases, the current will increase at the exact
same rate
R = V / I
For a constant resistance, if the voltage
increases, the current must increase at the
exact same rate.

6. Node – Any point where 2 or more circuit elements
are connected together.
+
-
Vs Is
R1
R2 R3
+
Vo
-

7. Branch – A circuit element between
two nodes
+
-
Vs Is
R1
R2 R3
+
Vo
-

8. Loop – A collection of branches that form a
closed path returning to the same node without
going through any other nodes or branches
twice
+
-
Vs Is
R1
R2 R3
+
Vo
-
A B
C

9. Kirchhoff’s Voltage Law (KVL)
The algebraic sum of voltages around each loop
is zero
– Beginning with one node, add voltages across
each branch in the loop (if you encounter a + sign
first) and subtract voltages (if you encounter a –
sign first)
Σ voltage drops - Σ voltage rises = 0
Or Σ voltage drops = Σ voltage rises

10. Example
+
-
Vs Is
R1
R2 R3
+
Vo
-
A B
C
I2
I1
+
I2R2
-
+ I1R1 -
Assign current variables and directions

11. Example
+
-
Vs Is
R1
R2 R3
+
Vo
-
A B
C
I2
I1
+
I2R2
-
+ I1R1 -
Starting at node A, add the 1st voltage drop: + I1R1

12. Example
+
-
Vs Is
R1
R2 R3
+
Vo
-
A B
C
I2
I1
+
I2R2
-
+ I1R1 -
Add the voltage drop from B to C through R2: + I1R1 + I2R2

13. Example
+
-
Vs Is
R1
R2 R3
+
Vo
-
A B
C
I2
I1
+
I2R2
-
+ I1R1 -
Subtract the voltage rise from C to A through Vs: + I1R1 + I2R2 – Vs = 0
Notice that the sign of each term matches the polarity encountered 1st

14. Kirchhoff’s Current Law
The sum of incoming
currents at a node is
equal to the sum of
outgoing currents at
that node. Gustav Kirchoff
was an 18th
century German
mathematician  0i

15. i1 flows into the node
i2 flows out of the node
i2 flows out of the node
i2 i3
node
i1 = i2 + i3

16. 16
Kirchhoff’s Current Law applies to all types of networks
f1
f1
f2
f3
“KCL” for blood flow:
f1 = f2 + f3
Human Blood Vessels (f is blood flow rate)
Organ

17. Method of Circuit Analysis:
Node Analysis:
 Find different nodes
Select a node as a reference
node.
Assign voltages
Apply KCL at each nodes
Solve the resulting equation
by KCL.

18. Mesh Analysis
Find out the loop
Assign currents
Apply KVL at each
loop.
Solve the resulting
equation from
KVL.

19. Thanks all