resist (series parallel) v1

8/4/2019 Resist (Series Parallel) v1

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Resistors in Series and Parallel

Name: ( ) Class: Date:

Learning objectives Recognise that the resistance of a circuit can be varied by arranging resistors in series or parallel

Activity 1) Series Circuit (1 Resistor)a) Start the Circuit Construction Kit simulation.

b) Make a series circuit using the following components as shown in the diagram.i. Battery

ii. Light bulbiii. Ammeter

c) Turn on Show Values so you see the resistor values

Diagram 1

d) Change the voltage of the battery to 18 V ( Right click on the battery, select Change Voltage)e) Measure the potential difference across the resistor, i.e across AB.f) Record the potential difference, current in the table in page 4g) Calculate the resistance across AB of the circuit and record it in the table in page 4.

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AB


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Activity 2) Series Circuit (2 Resistors in series)a) Add a resistor in series to the circuit as shown in the diagram below. Observe what happens to

the brightness of the bulb.

Observation: The bulb becomes brighter / dimmer / remain the same (circle the correct answer )

Diagram 2

b) Measure the potential difference across the resistors, i.e across AB.c) Record the potential difference and current in the table in page 4d) Calculate the resistance across AB of the circuit and record in in the table in page 4.e) Compare the resistance across AB, current and brightness of the bulb.

We can conclude that by adding another resistor in series to the circuit,

i. the resistance across AB increases / decreases / remain the same

ii. the current increases / decreases / remain the same

iii. The bulb becomes brighter / dimmer / remain the same

(Optional)f) Remove one of the resistors. DO NOT CONNECT ANYTHING

What happens to the bulb?

The bulb becomes brighter / dimmer / remains the same / did not light up(circle the correct answer )

This is because there is a in the circuit.

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A B


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2) Parallel Circuit (2 Resistors in Parallel)a) Set up the circuit in diagram 1 again.

b) Add a resistor in parallel to the circuit, as shown in diagram below

Diagram 3

c) Observe what happens to the brightness of the bulb.

Observation: The bulb becomes brighter / dimmer / remain the same (circle the correct answer )

d) Measure the potential difference across the resistors, i.e across AB e) Record the potential difference and current in the table below and calculate the resistance

across AB of the circuit.f) Compare the resistance across AB, current and brightness of the bulb. We can conclude that by

adding another resistor in parallel to the circuit,

i. the resistance across AB increases / decreases / remain the same

ii. the current increases / decreases / remain the same

iii. The bulb becomes brighter / dimmer / remain the same

(Optional)g) Remove one of the resistors. What happens to the bulb?

The bulb becomes brighter / dimmer / remains the same / did not light up(circle the correct answer )

This is because there is still a c path in the circuit for current to flow.

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A B


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PotentialDifference, V (V)

Current, I (A)Resistance across AB,

I

V = )R(

1 resistors

2 resistors in series

2 resistors in parallel

Questions1) When placing a voltmeter in a circuit, does it go in series or parallel?

2) When placing an ammeter in a circuit, does it go in series or parallel?

3) Light bulbs and motors have resistance. When light bulb blows, it is the same as removing aresistor. What are the advantages of placing lights and motors in parallel?

4) Arrange the following in order of i. Increasing overall resistance

ii. Increasing current, assuming voltage is constant.

(optional)5) You are supplied with the following components: batteries, resistors, switches, wires and a light bulb . With the help of a diagram, describe how you will design a circuit such the brightness of the light

bulb can be set to any of these 3 brightness level: dim , bright , brightest .

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(a) (b) (c)

resist (series parallel) v1

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