Ohm’s law

Lab# 18

Abstract

The specific objective of this lab is to determine was to analyze the relationship between voltage and current in a given resistor.

Introduction

Current is the flow of an electrical charge, which is expressed in amperes (amps). Voltage is the electromotive force (potential difference), which is expressed in volts. Resistance is the material’s opposition to the flow of electric current which is measured in ohms. Ohms’ Law is the law that states electrical current is proportional to voltage and inversely proportional to resistance. The ammeter (measures amperes) is connected in series with in a circuit. The voltmeter (measures volts is connected in parallel within a circuit.

Diagram

Procedure

1. Do not turn on the power source. Properly wire the circuit with the power source the voltmeter and the ammeter. Leave the circuit open for resistors and get teachers approval before moving on.

2. Draw the circuit with resistors where it was left open.

3. Using the resistor in circuit 1, connect the wires and adjust the power supply so that the current listed first is read on the ammeter. Read and record data in the table.

4. Using the same resistor adjust the power supply so that the ammeter records the second current. Record the data.

5. Repeat steps 3 and 4 for the rest of the circuits.

6. Apply Ohms Law to the data and calculate resistivity

Analysis

Printed value of resistor Tolerance range Current

(mA) Current

(A) Voltage

(V) Resistance

(Ohms)

Circuit1 Resistor 1 60ohms +/-3.00ohms 100mA .10A

.32A 6.2V

19.8V 61.94ohms

Circuit2 Resistor2

120ohms +/-6.25ohms 100mA

150mA .10A

.15A 13V

19.7V 130.65ohms

Circuit3 Resistor3 150ohms +/- 7.50ohms 40mA

60mA .04A

.06A 7v

9.6V 167.5ohms

Circuit4 Resistor4

10ohms +/-.50ohms 100mA

200mA .10A

.20A 1V

2V 10ohms

Percent error: circuit1- 3.23%, circuit2- 4.52, circuit3-11.68%, and circuit4- 0%

Conclusion

The only resistor that was...