CircuitJS/C2/Wheatstone-Bridge/English
| Visual Cue | Narration |
| Slide:1 | Welcome to the spoken tutorial on Wheatstone Bridge usingCircuitjs simulator. |
| Slide 2:
Learning Objective |
In this tutorial, we will learn how
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| Slide 3:
System Requirement |
To record this tutorial, I am using:
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| Slide 4:
Prerequisite |
To follow this tutorial, you should have a basic knowledge of,
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| Wheatstone.png | We will make this circuit for the Wheatstone Bridge demonstration. |
For a Wheatstone Bridge circuit, we require,
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| Click on File and select New Blank Circuit. | Let us open the Circuitjs interface.
In the menu bar, click on File and select New Blank Circuit. |
| Click on the Draw option >> select Add resistor.
Click and drag to draw a resistor. Right-click on the resistor >> select the Duplicate option. |
Click on the Draw option and select Add resistor.
Click and drag to draw a resistor as shown. By default, the value of this resistor is 1 Kilo Ohm. We need 4 resistors for this circuit. Right-click on the resistor, and select the Duplicate option. This will generate a resistor of the same value. Repeat this process till you have 4 resistors in the work area. Align all these resistors in the same manner as shown.
Make sure they all are connected.
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| Use the Add Text option to give labels to these multiple resistors.
Give the labels as P, Q, R, and S respectively as shown. | |
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Point to junction |
After this connection, we can see that multiple junctions are formed.
To denote these junctions use theAdd Text option to label them. Give labels as A,B, C, and D to these junctions as shown. |
| Show the path to find the DC power supply and draw it
Click on Draw, >> Inputs and Sources >>select Add Voltage Source (2-terminal). Change the DC power supply value |
Next, we have to include theDCpowersupply.
Click on Draw, go to Inputs and Sources. Select Add Voltage Source (2-terminal). Drag and draw the DC power supply in the working area. Change the voltage value of theDC power supply to12V. |
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Click onDraw >> go to thePassive Component. Select the Switch component. Drag and draw the Switch in the work area. |
We also need a Switch to turn ON and OFF the circuit.
Click onDraw and go to thePassive Component. Then select the Add Switch to select the switch component. Drag and draw the Switch in the work area. Connect the switch in series with the DC power supply. |
| In an ideal Wheatstone Bridge circuit, a galvanometer is used to calculate the current.
As Circuitjs platform does not have a galvanometer component, we will use an Ammeter. | |
| Click on Draw, go to Outputs and Labels
Select the Add Ammeter. Point to the circuit. |
Click on Draw, go to Outputs and Labels and
Select the Add Ammeter. Draw it by dragging the cursor in the working area. Connect the Ammeter between junctions B and D as shown in the circuit. |
| We have all the required components in the work area.
Now let's connect the components using wires. | |
| From the Draw menu, select Add wire.
Drag and draw a wire |
From the Draw menu, select Add wire.
Drag and draw a wire by selecting the end points of the components as shown in the video. Connect the junction A to the DC power supply. Connect the junction C to the switch. |
| Observe the yellow dots | Observe the yellow dots indicating the current flow direction in the circuit.
If you cannot see the yellow dots moving consistently, increase the current speed bar. The current speed bar is available at the right-top corner of your screen. |
| Change the P,Q,R,S resistor values to 200, 400 and 400 ohms respectively | Let us now change the value of these resistors.
Change the values of resistor P to 200 ohms. Change the value of resistor Q and R to 400 ohms. Let S be the unknown resistor. Ignore the value of resistor S shown in the circuit. Notice that the current value shown by the ammeter is 1.36 milli ampere. |
| Slide:
Wheatstone Bridge - Balanced condition |
The Wheatstone Bridge is in a balanced condition, when the below conditions are fullfilled.
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| Slide: Find unknown resistance
Wheatstone-balance.png P = 200 Ohms Q = 400 Ohms R = 400 Ohms S = ? |
Let us find the value of resistor S using the Wheatstone Bridge balanced condition formula.
The values of resistors are, P = 200 Ohms Q = 400 Ohms R = 400 Ohms S = is unknown The balanced condition formula P/Q = R/S becomes, S = R x Q / P Put the values of these resistors in the formula. After calculation, the value of resistor S is 800 Ohms. |
| CircuitJS simulation window
Point to ammeter value |
Now, let us go back to the Circuitjs simulation.
Let us change the value of resistor S to 800 ohms using the edit option. Now the ammeter shows zero value. This shows the Wheatstone Bridge is in balanced condition. |
| This brings us to the end of the tutorial.
Let us summarize. | |
| Slide Summary | In this tutorial, we learnt how
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| Slide:
Assignment |
As an assignment,
Change the values of resistor P to 60 ohms, resistor Q to 150 ohms, resistor R to 300 ohms. Use the Wheatstone Bridge balance condition formula to find the value of resistor S. |
| Slide :
About Spoken Tutorial project |
The video at the following link summarizes the Spoken Tutorial project.
Please download and watch it. |
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| Acknowledgement | Spoken Tutorial project was established by the Ministry of Education(MoE), Govt of India |
| Thank you | This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.
Thank you for joining. |
