OHM’S LAW

a. To know the difference between current, voltage and resistance.

b. To appreciate the contribution of Georg Simon in the field of electricity.

c. To be able to solve current voltage and resistance.

I. OBJECTIVES

II. INTRODUCTION How will an increase in potential difference (voltage) or an increase in resistant affect the current flowing into the wires? Solving the amount of voltage, current and resistivity is very important. In electricity it helps electricians to determine the right size of wire to be use in wiring houses.

OHM’S LAW

III. LESSON OHM’S LAW (1826)

- Is a mathematical formula that expresses the relationship between electromotive force, electric current and resistant in a current. - in honor to Physicist Georg Simon

Ohm. Current is directly proportional to voltage and inversely proportional to resistance.

OHM’S LAW

1. Voltage (E) - electrical pressure (emf). - Measured in volts (V).

2. Current (I) - electron flow. - measured in ampere (A).

3. Resistant (R) -The opposition to current flow or controls movement of electrons. - measured in Ohm (Ω).

DEFINITION OF TERMS

4. Electrical Energy (En) - measured in Kilo Watt Hour (KWh). 5. Power (P) - Measured in Watts (W).

6. Time (t) - measured in hours (hrs).

FORMULA: 1. E=IR, I=E/R, R=E/I 2. Power=Current(I)×Voltage (E) 3. Electrical Energy=Pt/1000

EXAMPLES:

1.Given: E= 24V R= 6Ω I=?

Solution: I=V/R I= 24V/6Ω = 4 Ampere

Solution: R=E/I P=IE (Solve first for power) =(220V)(3A) =660 Watts R=220V/3A =73.3Ω

2.Given: E=220 I=3A R=? P=?

3.Given:Pt/1000 P=800 W t= 3 hrs En= ?

Solution: En=Pt/1000 =(800W)(3W)/1000 =2.4 KWh

1.Calculate the amount of current in a circuit, given values of voltage and resistance. E= 12V R= 3Ω I= ?

IV. ACTIVITY

2. Calculate the amount of resistance in a circuit ,given values of voltage and current.

V= 36 V I= 4 A R=?

3. Calculate the amount of voltage supplied by a battery, given values of current and resistance.

I= 2 A R= 7 Ω V=?

http://www.allaboutcircuits.com/vol_1/chpt_2/1.html

PREPARED BY:

Carlo P. Pilay

Aldo T. Benes

Philbert Punasen