CircuitJS/C2/Series-and-Parallel-Resistance/English

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Visual Cue Narration
Slide 1: Welcome to the spoken tutorial on Series and Parallel Resistance circuits.
Slide 2:

Learning Objective

In this tutorial, we will learn how,
  • To connect Resistors in series and parallel circuits
  • Voltage and current characteristics behave in series and parallel circuits.
Slide 3:

System Requirement

To record this tutorial, I am using:
  • Ubuntu Linux 20.04 OS
  • CircuitJS Application
Slide 4:

Prerequisite

To follow this tutorial, you should have a basic knowledge of
  • Electrical circuits

Series Resistance.png


We will create this series resistor circuit for demonstration.

For this circuit we require:

  • Three resistors of 1 Kilo Ohms
  • One Ammeter
  • One Switch and
  • One 12 Volts DC Power Supply
Let us open the circuitjs interface.
First, we will create a simulation circuit for the resistors connected in series.
Draw => Add Resistor

Right-click => Duplicate

Click on File and select New Blank Circuit.

Click on the Draw option in the menu bar and select Add resistor.

Click and drag to draw a resistor as shown.

By default, the value of this resistor is 1 Kilo Ohms.

We need three resistors with the same values.

Right-click on the resistor and select the Duplicate option.

Place the resistor as shown here.

Repeat the same process one more time to get three resistors in the circuit.

Connect them in series as shown.

Using the Add Text option, name the multiple resistors as R1, R2, and R3.

Arrange the text as shown.

Draw => Inputs and Sources => Add Voltage Source Right-click =>Swap Terminal

Right Click => Edit..

Next, we have to add the DC power supply.

Click on Draw, go to Inputs and Sources.

Then select Add Voltage Source (2-terminal).

Refer to the circuit diagram shown above to check the polarity of the DC power supply.

To change the polarity, right-click on the source and select the Swap Terminal option.

Notice the change in the polarity of the power supply.

The default value of this power supply is 5 volts.

For our circuit, we need the DC power supply to be 12 Volts.

To change the value of the power supply, right-click on the power supply.

Select Edit option. Change the value from 5 to 12 in the given box as shown.

Click on the OK button to save the changes.

Draw => Passive Components => Add Switch We also need a switch to turn ON and OFF the circuit.

In the Draw menu, select Passive components, and then select Add switch.

Draw => Outputs and Labels => Add Ammeter

We need to add an ammeter to calculate the current flowing in the circuit.

In the Draw menu, go to Outputs and Labels, and select Add Ammeter option.

Place the ammeter between the resistor and the switch as shown.

Connect the circuit using wire We have all the required components in the work area.

Now let's connect the components using wires.

Draw => Add Wire From the Draw menu, select Add wire.

Connect the ammeter to the switch as shown. Connect the R3 resistor to the power supply to complete the circuit.

Point to yellow dots Observe the yellow dots, indicating the current flow direction in the circuit.

Observe the current reading across the ammeter.

Place the mouse cursor on a particular component to get its characteristics.

Place the mouse cursor on resistor R3.



Notice the block at the bottom of your screen representing its values.

It shows the resistor value as 1 Kilo Ohm.

Voltage drop is 4 Volts and it is denoted by Vd.

Current flowing through the resistor is 4 milli-Amperes.

Power denoted by P is 16 milli-Watt.

Let us change the resistor R2 value from 1 Kilo Ohm to 3 Kilo Ohms.

Notice the change in the value of the current flowing through these resistors.

In a series circuit:

- The current flowing through each resistor is same

- The sum of voltage drops across each resistor is almost equal to the applied DC power supply.

Slide: Assignment

Series Resistance

Slide change

As an assignment do the following
  1. In the same circuit, change the value of resistors as
  2. R1 = 4KOhms, R2 = 2KOhms, R3 = 100 Ohms. Change the DC Power supply voltage to 5 Volts.
  3. Notice the current flowing and voltage drop at each resistor.
Only Narration. Similarly, we will build a circuit with resistors connected in parallel.
Show the diagram

Parallel Resistance.png

arrows

We will create this parallel resistor circuit for demonstration.

For this circuit we require

  • Three resistors of 1K Ohms
  • Four Ammeters
  • One Switch
  • One 12 Volts DC Power Supply
Click on File and select New Blank Circuit. Click on File and select New Blank Circuit.



Click on the Draw option in the menu bar and select Add resistor.

Click and drag to draw a resistor as shown.

By default, the value of this resistor is 1 Kilo Ohms.

We need three resistors with the same value.

Right-click on the resistor and select the Duplicate option. Place the resistor as shown.

Repeat the same process one more time to get three resistors in the circuit.

Place these three resistors parallel to one another as shown here.

Using the Add Text option, name these multiple resistors as R1, R2, and R3.

Arrange the text as shown.

Draw => Inputs and Sources => Add Voltage Source Next, we have to add the DC power supply.

Click on Draw, go to Inputs and Sources, and select Add Voltage Source (2-terminal).

Refer to the circuit diagram shown above to check the polarity of the DC power source.

Right Click => Edit. The default value of this power supply is 5 volts.

For our circuit, we need 12 Volts.

To change the value of the power supply, right-click on the power supply.

Select the Edit option.

Change the value from 5 to 12 in the given box as shown.

Click on the OK button to save

the changes.

Draw => Passive Components => Add Switch We also need a switch to turn ON and OFF the circuit.

In the Draw menu, select Passive components, and then select Add switch.

Connect the switch to the DC power supply as shown.

Draw => Outputs and Labels => Add Ammeter We need four Ammeters in the circuit.

Select the Draw menu, go to Outputs and Labels, and select the Add Ammeter option.

Drag and draw the ammeter in the working space.

Use the Duplicate option three times to get four Ammeters in the working space.

Connect one ammeter to each resistor as shown.

Connect the fourth ammeter to the switch as shown.

Connect the circuit using wire We have all the required components in the work area.

Now let's connect the components using wires.

Draw => Add Wire From the Draw menu, select Add wire.

Draw wires from each ammeter connected to these three resistors to form junctions A and B.

Now, connect junction A to the Ammeter and junction B to the DC power supply.

Observe the yellow dots indicating the current flow direction in the circuit.

Observe the current reading across the Ammeter in the circuit.

The sum of all three ammeters connected in parallel equals the ammeter connected in the circuit.

Notice the current flowing and voltage drop at each resistor.

Slide: Assignment

Parallel Resistance


As an assignment,
  • Change the DC voltage supply value to 5V.
  • Notice the change in voltage and current for each resistor.
Compare Series and Parallel Resistor circuit.


Let us compare the series and parallel circuits.

In a circuit where resistors are connected in series

  • The amount of current flowing through each resistor is the same.
  • But the voltage drop across each resistor is different.

In a circuit where resistors are connected in parallel

  • The current splits up at the junction and is different through each resistor.
  • But the voltage across each resistor is the same.
Analogy

(show it with the circuit break in both series and parallel diagrams)

Parallel connection circuits are used to connect multiple electrical appliances.

E.g. Home, Industrial area

Let us find out the reason behind this.

Only Narration Let us first take an example of a series connection circuit.

Assume there are three LEDs connected in series instead of three resistors.

Three LEDs are denoted with L1, L2, L3 respectively.

Assume that, L2 LED gets broken or is faulty.

To implement this condition, we will remove the L2 LED from the circuit.

This will result in the circuit not completing its path.

So the current is not flowing through the circuit as shown here.

Show Parallel connection circuit with disconnected 2nd resistor Assume that three LEDs L1, L2, L3 are connected in a parallel circuit.

Let us take the same faulty L2 LED example, as shown in the series circuit.

Remove the L2 LED from the circuit.

Notice that the current still flows through the L1 and L3 LEDs.

In a parallel circuit, if one component is faulty, the rest of the circuit keeps working smoothly.

This brings us to the end of the tutorial. Let us summarize.
Slide Summary In this tutorial, we learnt how
  • To connect resistors in series and parallel circuits
  • Voltage and current characteristics behave in series and parallel circuits
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Thank you This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.

Thanks for watching.

Contributors and Content Editors

Madhurig, Nirmala Venkat