# Verify Ohm’s Law, Series and Parallel Circuits

Essay by   •  October 4, 2018  •  Lab Report  •  1,243 Words (5 Pages)  •  187 Views

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Title of lab experiment:

Experiment to verify ohm’s law, series and parallel circuits

Aim01: Determine the resistances of the different resistor on the PC board with the help of DMM .

Aim02: Determine the current and voltage through the resistor in series and parallel with an applied voltage of 2.5V.

Introduction:

Ohm’s law stating that electric current is inversely proportional to the resistance and proportional to the voltage.

I=V/R(ohm’s  law)

V=Voltage

I=Current

R=Resistance

There are two basic ways in which to connect more than two circuit component which is known as series and parallel. If the electric device is connected in series, components are connected end-to end in a line to form a single path that individual charge would pass through each one of the light bulbs in consecutive rule. If the electric device is connected in parallel, all components are connected across each other’s leads that a single charge passing through the external circuit would only pass through one of the light bulbs.

Method:

Experiment part:01

Measured the resistance of three resistor by connected the lead to common terminal and another one is to volt-ohm-hertz terminal of DMM by set the scale to 200 ohms.

Common terminal end of DMM should be connected to the common terminal (common to three resistor and light bulb) in circuit, plugged the end of Vol-Ohm-Hertz to 10-ohm resistor in circuit board to find out the resistance. Repeated the previous step to find out resistance of 33 and 100-ohm resistor.

Measured the voltage and current at applied Voltage ranging from 0.5 to 3V, set the Multimedia to 10 Amp scale and move the lead of volt-ohm-hertz to 10A. Used two red leads instead of black lead to measure the current within the circuit. Connected one of lead to the power supply which act as positive lead in through the 10 Ohm resistor in the circuit (DMM), connected the black lead from Multimeter to the negative terminal of power supply. In order to complete the circuit, turned on the G-xplorer, which act as a multimedia to measure the voltage and current directly across the resistor, adjusted the fine voltage to get 0.5V and continued the measurement of voltage, which ranging from 0.5V to 3V. If it is not over 200mA when the lead was plug in the 10A, you may need to use the current as a mA scale in order to get accurate result. Repeated the previous step for the 33Ohm and 100 Ohm and recorded the result.

Experiment Part :02

Complete the circuit by plug the red lead to the power supply, which act as positive terminal through the ammeter to circuit board. Connected the 10 ohm and 33 ohm resistors in series, the end lead comes from ammeter must plugged in first resistor (10ohm) resistor whereas the black lead will connected from second resistor (30-ohm) to negative terminal of power supply. Connect the G-xplorer and adjust the fine voltage to get 2.50V in order to measure the resistance in series. Measured and recorded the series resistance combination of following resistors. 10 and 33 Ω, 10 and 100 Ω, 33 and 100 Ω.

For the parallel combination, the black lead will have plugged in common terminal to the negative terminal of power supply, take another black lead to shorten the 30 and 100ohm terminal, power supply connected to the terminal of 100 ohm by the red lead. Moved the terminal of resistors to find out the parallel resistance combination of following. 10 and 33 Ω, 10 and 100 Ω, 33 and 100 Ω. Recorded the results in given tables in the excel sheet and commented whether the law of combination of resistors in series and in parallel are verified. Repeat the previous steps by replace the three resistors with the three light bulbs on the circuit board and recorded the brightness of bulb for each setup.

Part one Result:

Measured the resistance of the three resistors.

 Nominal resistance (Ω) Measured resistance, R (Ω) 10 10.5 33 33.9 100 99.0

10 ohms

 Applied voltage, Vo (V) Measured voltage across resistor, VR (V) Measured Current, I (A) Resistance, R (Ω) 0.5 0.5 0.05 10.0 1.0 1.17 0.12 9.75 1.5 1.61 0.16 10.06 2.0 2.11 0.21 10.05 2.5 2.59 0.26 9.96 3.0 3.09 0.31 9.97

[pic 1]

Ohm’s law is verified.

33 ohms

 Applied voltage, Vo (V) Measured voltage across resistor, VR (V) Measured Current, I (A) Resistance, R (Ω) 0.5 0.70 20.7mA 33.8 1.0 1.15 34.3mA 33.5 1.5 1.58 46.8mA 33.7 2.0 2.07 61.3 mA 33.7 2.5 2.51 74.8mA 33.6 3.0 2.93 87.2mA 33.6

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