Presentation Ohm Law

1. Presentation by Nabeel Isa

2. V
Introduction
Ohm’s law states that the current through a conductor is directly
proportional to voltage. We use the inverse of resistance as a proportional
constant. The mathematical form of this law is:
I=
𝑽
𝑹

3. Ohm’s Law
Current through an ideal conductor is
proportional to the applied voltage
– A Conductor is also known as a resistor
– An ideal conductor is a material whose resistance does not change with
temperature
For an ohmic device,
Voltage =Current  Resistance
V =I R
V
V = Voltage
I = Current
R = Resistance
(Volts = V)
(Amperes = A)
(Ohms = Ω)

4. Current and Voltage Defined
Conventional Current: (the current in electrical circuits)
Flow of current from positive terminal to the negative terminal.
- has units of Amperes (A) and is measured using ammeters.
Voltage:
Energy required to move a charge from one point to another.
- has units of Volts (V) and is measured using voltmeters.

5. Voltage and Current Relationship for
Linear Resistors
Voltage and current are linear when resistance is held constant.
Voltage versus Current for
a 10 ohmResistor
0.6
0.5
0.4
0.3
0.2
0.1
0
0 1 2 4 5 63
Voltage (V)
Current(A)

6. Kirchhoff’s Current Law
=0
Iin = I1 + I2 = Iout
Iin - Iout
Current into junction = Current leaving junction
Iin =Iout
The amount of current that enters a junction is equivalent to the
current amount that leaves the junction.

7. Kirchhoff’s Voltage Law
Sum of all voltage rises and voltage drops in a circuit (a
closed loop) equals zero
Vin = Voltage Across Each Resistor
Vin =V1=V2 =...
Net Voltage for a circuit = 0
V1 V2
V =V1+V2
V -V1 -V2 = 0
V

8. Conclusion
Ohmic resistors obey Ohm’s Law linearly
V = I  R
Resistance is affected by temperature.
The resistance of a conductor increases as its
temperature increases.