Experiment No. 1 Ohm’s Law Electrical Engineering Department Third Year E/C Digital Electronic Circuits Experiment No. 1 Ohm’s Law Prepared by: Diary R. Sulaiman 2018 Prepared by: Diary R. Sulaiman

Contents - Introduction - Basic Defitions - Electrical meters - Electrical Power supplu - Connections and facilities - Results -Remarks Prepared by: Diary R. Sulaiman 2

All electrical circuits require three elements. A voltage source , that is, a battery or power supply. + - (2) A conductor to carry electrons from and to the voltage source The conductor is often a wire. (3) A resistance or Load. A point where energy is extracted form the circuit in the form of heat, light, motion, etc.

In electrical circuits, Ohm's law states that the current through a conductor between two points is directly proportional to the potential difference or voltage across the two points, and inversely proportional to the resistance between them I= V / R

All electrical circuits require three elements. A voltage source, a battery or power supply. (2) A conductor to carry electrons from and to the voltage Source, The conductor is often a wire. (3) A resistance or LOAD. A point where energy is extracted form the circuit in the form of heat, light, motion, etc.

Potential Rise Across a Power Source volts current current Battery Electrons have More Energy Electrons have Less Energy Electrons get An energy boost

Potential Drop Across a Resistor volts current Resistor Electrons have Less Energy Electrons have More Energy Energy is lost In the resistor

(1) VOLTMETER – MEASURES THE IT IS MEASURED IN VOLTS (V, mV,…)) measuring devices OR METERS (1) VOLTMETER – MEASURES THE IT IS MEASURED IN VOLTS (V, mV,…)) (2) AMMETER–.IT IS MEASURES IN CURRENT (A, mA,..) (3) OHMETER– IT IS MEASURES RESISTANCE (, k, m, …) (4) MULTIMETER– MEASURED ALL THESE QUANTITIES. M A O V

Electrical Meters volts AMPS Voltmeters measure potential in volts Ammeters measure current in amperes and are always wired in series in the circuit. AMPS Voltmeters measure potential in volts and are always wired in parallel in the circuit. volts

CONNECTION OF Meters AMMETER: is connected in series, while VOLTMETER: is connected in parallel

An actual meter

Electrical Symbols A V battery + - AC generator wiring voltmeter ammeter A Variable resistance resistance

figure 1 PROCEDURE Connect the circuit shown in figure 1. Have the instructor inspect your circuit before applying power. Slowly increase the voltage across the resistor from 0V to 10V in approximately 1V increments. Record the measured voltages and currents from your multimeter as in table 1. V (Volts) I (mA) Fig.1 Fig.2 Fig.3 1 2 3 4 5 6 7 8 9 10 figure 1