Difference between revisions of "CircuitJS/C3/Silicon-Diode-Characteristics/English"

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(Created page with "{| border="1" |- || '''Visual Cue''' || '''Narration''' |- || '''slide:1''' || Welcome to the spoken tutorial on '''Silicon''' '''Diode Characteristics''' using '''CircuitJS''...")
 
Line 6: Line 6:
 
|| '''slide:1'''
 
|| '''slide:1'''
 
|| Welcome to the spoken tutorial on '''Silicon''' '''Diode Characteristics''' using '''CircuitJS''' simulator.
 
|| Welcome to the spoken tutorial on '''Silicon''' '''Diode Characteristics''' using '''CircuitJS''' simulator.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Slide 2:'''
 
|| '''Slide 2:'''
  
 
'''Learning Objective'''
 
'''Learning Objective'''
 
|| In this tutorial, we will learn about
 
|| In this tutorial, we will learn about
* <div style="margin-left:1.27cm;margin-right:0cm;">Voltage-Current(V-I) characteristics of '''Silicon''' diode in forward and reverse bias.</div>
+
* Voltage-Current(V-I) characteristics of '''Silicon''' diode in forward and reverse bias.
  
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Slide 3:'''
 
|| '''Slide 3:'''
  
 
'''System Requirement'''
 
'''System Requirement'''
 
|| To record this tutorial, I am using:
 
|| To record this tutorial, I am using:
* <div style="margin-left:1.27cm;margin-right:0cm;">Ubuntu Linux 20.04 OS</div>
+
* Ubuntu Linux 20.04 OS
* <div style="margin-left:1.27cm;margin-right:0cm;">'''CircuitJS''' Application</div>
+
* '''CircuitJS''' Application
  
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Slide 4:'''
 
|| '''Slide 4:'''
  
 
'''Prerequisite'''
 
'''Prerequisite'''
 
|| To follow this tutorial, you should have a basic knowledge of
 
|| To follow this tutorial, you should have a basic knowledge of
* <div style="margin-left:1.27cm;margin-right:0cm;">Electrical circuits</div>
+
* Electrical circuits
  
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Slide 5:'''
 
|| '''Slide 5:'''
  
 
'''What is a Diode?'''
 
'''What is a Diode?'''
 
||  
 
||  
* <div style="margin-left:1.27cm;margin-right:0cm;">Diode is a semiconductor device with two terminals.</div>
+
* Diode is a semiconductor device with two terminals.
* <div style="margin-left:1.27cm;margin-right:0cm;">These terminals control the flow of electrons in a circuit.</div>
+
* These terminals control the flow of electrons in a circuit.
* <div style="margin-left:1.27cm;margin-right:0cm;">Diodes can be used as rectifiers, switches, voltage regulators etc. </div>
+
* Diodes can be used as rectifiers, switches, voltage regulators etc.  
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Slide 6:'''
 
|| '''Slide 6:'''
  
Line 43: Line 43:
 
'''Diode_Symbol.png'''
 
'''Diode_Symbol.png'''
 
||  
 
||  
* <div style="margin-left:1.27cm;margin-right:0cm;">Diode is represented with this symbol.</div>
+
* Diode is represented with this symbol.
* <div style="margin-left:1.27cm;margin-right:0cm;">The diode symbol has a triangle with a line across one vertex.</div>
+
* The diode symbol has a triangle with a line across one vertex.
* <div style="margin-left:1.27cm;margin-right:0cm;">The vertex side of the triangle is cathode.</div>
+
* The vertex side of the triangle is cathode.
* <div style="margin-left:1.27cm;margin-right:0cm;">The base side of the triangle is an anode of the diode.</div>
+
* The base side of the triangle is an anode of the diode.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Slide:'''
 
|| '''Slide:'''
  
Line 54: Line 54:
  
 
There are two ways of Biasing:
 
There are two ways of Biasing:
# <div style="margin-left:1.27cm;margin-right:0cm;">'''Forward Bias '''and</div>
+
# '''Forward Bias ''' and
# <div style="margin-left:1.27cm;margin-right:0cm;">'''Reverse Bias'''</div>
+
# '''Reverse Bias'''
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| '''Forward Bias'''
 
|| '''Forward Bias'''
  
Line 62: Line 62:
  
 
|| In forward bias,
 
|| In forward bias,
* <div style="margin-left:1.27cm;margin-right:0cm;">The positive terminal of the power supply is connected to the P-Junction or anode of diode</div>
+
* The positive terminal of the power supply is connected to the P-Junction or anode of the diode
* <div style="margin-left:1.27cm;margin-right:0cm;">The negative terminal of the power supply is connected to the N-junction or cathode of the diode</div>
+
* The negative terminal of the power supply is connected to the N-junction or cathode of the diode
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
||  
+
|| Show the circuit diagram
 
|| We will make this circuit to explain forward bias characteristics of the diode.
 
|| We will make this circuit to explain forward bias characteristics of the diode.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Show the diagram
 
|| Show the diagram
  
Line 73: Line 73:
  
 
|| For Forward bias diode circuit, we require,
 
|| For Forward bias diode circuit, we require,
* <div style="margin-left:1.27cm;margin-right:0cm;">Variable voltage (That is, 0 volts to 2 volts)</div>
+
* Variable voltage (That is, 0 volts to 2 volts)
* <div style="margin-left:1.27cm;margin-right:0cm;">Diode</div>
+
* Diode
* <div style="margin-left:1.27cm;margin-right:0cm;">Ammeter</div>
+
* Ammeter
* <div style="margin-left:1.27cm;margin-right:0cm;">1 Ohm resistor</div>
+
* 1 Ohm resistor
* <div style="margin-left:1.27cm;margin-right:0cm;">Ground</div>
+
* Ground
  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Keep the circuit diagram on top right
 
|| Keep the circuit diagram on top right
 
|| Let us open the '''CircuitJS''' interface.
 
|| Let us open the '''CircuitJS''' interface.
  
 
In the menu bar, click on '''File''' and select '''New Blank Circuit'''.
 
In the menu bar, click on '''File''' and select '''New Blank Circuit'''.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select variable voltage'''
 
|| '''Select variable voltage'''
 
 
|| Click on '''Draw''', go to '''Inputs and Sources''', and select '''Add Variable voltage'''.
 
|| Click on '''Draw''', go to '''Inputs and Sources''', and select '''Add Variable voltage'''.
  
Line 98: Line 97:
  
 
Click on the '''OK''' button to save the changes.
 
Click on the '''OK''' button to save the changes.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select Diode'''
 
|| '''Select Diode'''
 
|| Click on '''Draw''', go to '''Active Components''', and select '''Add Diode''' option.
 
|| Click on '''Draw''', go to '''Active Components''', and select '''Add Diode''' option.
Line 109: Line 108:
  
 
Connect the P-junction of the diode to the variable voltage in the circuit.
 
Connect the P-junction of the diode to the variable voltage in the circuit.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select Ammeter'''
 
|| '''Select Ammeter'''
 
|| Now, click on '''Draw''', go to '''Outputs and Labels''', and select '''Add Ammeter''' component.
 
|| Now, click on '''Draw''', go to '''Outputs and Labels''', and select '''Add Ammeter''' component.
Line 118: Line 117:
  
 
Next, we will connect a resistor to the ammeter.
 
Next, we will connect a resistor to the ammeter.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select Resistor'''
 
|| '''Select Resistor'''
 
 
|| Go to '''Draw''', select '''Add resistor''' option.
 
|| Go to '''Draw''', select '''Add resistor''' option.
  
Line 128: Line 126:
  
 
Use the '''Edit''' option and change the resistor value to 1 Ohm.
 
Use the '''Edit''' option and change the resistor value to 1 Ohm.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select Ground'''
 
|| '''Select Ground'''
 
|| Now, we need a ground component to complete the circuit.
 
|| Now, we need a ground component to complete the circuit.
Line 137: Line 135:
  
 
Observe the yellow dots indicating the current flow in the circuit.
 
Observe the yellow dots indicating the current flow in the circuit.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
 
|| On the right side, you will see a slider to change the voltage value.
 
|| On the right side, you will see a slider to change the voltage value.
  
 
Use the slider to change the variable voltage value to 0 volts as shown.
 
Use the slider to change the variable voltage value to 0 volts as shown.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
 
|| We need a graph with relevant values of voltage and current.
 
|| We need a graph with relevant values of voltage and current.
  
 
These values will explain the V-I characteristics of a silicon diode.
 
These values will explain the V-I characteristics of a silicon diode.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Select View in New Scope and open graph'''
 
|| '''Select View in New Scope and open graph'''
  
Line 158: Line 156:
  
 
At the bottom left corner, you will see a '''Settings''' icon, click on it.
 
At the bottom left corner, you will see a '''Settings''' icon, click on it.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
||  
+
|| Change the graph
 
+
Change the graph
+
 
|| A pop-window will open.
 
|| A pop-window will open.
  
Click on the '''X-Y Plot''' option, and check the '''Show V vs I''' box.
+
Click on the '''X-Y Plot''' option, check the '''Show V vs I''' box.
  
 
Click on the '''OK''' button to save the changes.
 
Click on the '''OK''' button to save the changes.
Line 171: Line 167:
  
 
The current values are plotted on the Y-axis represented by the yellow line.
 
The current values are plotted on the Y-axis represented by the yellow line.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''FB_Observation Table.png'''
 
|| '''FB_Observation Table.png'''
 
|| Create a table to note down the current readings for the given voltage values.
 
|| Create a table to note down the current readings for the given voltage values.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''FB_0 volts.png'''
 
|| '''FB_0 volts.png'''
  
Line 182: Line 178:
 
Hence, the current value for this condition is 0 Ampere.
 
Hence, the current value for this condition is 0 Ampere.
  
Notice the dot in the graph, which shows the voltage and current values.
+
Notice the dot in the graph, it shows the voltage and current values.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Editing
 
|| Editing
  
Line 197: Line 193:
 
We can see the dot on the graph moving along the x-axis.
 
We can see the dot on the graph moving along the x-axis.
  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''FB_0.7 volts.png'''
 
|| '''FB_0.7 volts.png'''
 
|| As we increase the voltage value to 0.7 volts, the ammeter shows an increase in the current value.
 
|| As we increase the voltage value to 0.7 volts, the ammeter shows an increase in the current value.
Line 205: Line 201:
 
This point where the current increases is called the '''knee voltage'''.
 
This point where the current increases is called the '''knee voltage'''.
  
Thus, the''' knee voltage''' for the silicon diode is 0.7 volts.
+
Thus, the ''' knee voltage''' for the silicon diode is 0.7 volts.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Move the slider the slowly
 
|| Move the slider the slowly
 
'''FB_2 volts.png'''
 
'''FB_2 volts.png'''
Line 214: Line 210:
  
 
Hence for input voltage above 0.7 volts, the silicon diode acts as a conductor.
 
Hence for input voltage above 0.7 volts, the silicon diode acts as a conductor.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
|| Now let us see how a diode behaves in reverse bias mode.
+
|| Let us now see how a diode behaves in reverse bias mode.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Slide:
 
|| Slide:
  
 
'''Reverse_Bias_Diode.png'''
 
'''Reverse_Bias_Diode.png'''
 
|| In reverse bias,
 
|| In reverse bias,
# <div style="margin-left:1.27cm;margin-right:0cm;">The positive terminal of the power supply is connected to the '''N-Junction''' or '''cathode''' of the diode;</div>
+
# The positive terminal of the power supply is connected to the '''N-Junction''' or '''cathode''' of the diode;
# <div style="margin-left:1.27cm;margin-right:0cm;">The negative terminal of the power supply is connected to the '''P-junction''' or '''anode''' of the diode;</div>
+
# The negative terminal of the power supply is connected to the '''P-junction''' or '''anode''' of the diode;
  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''Reverse_Bias_Diode.png'''
 
|| '''Reverse_Bias_Diode.png'''
 
|| We will create this circuit to explain reverse bias characteristics of the diode.
 
|| We will create this circuit to explain reverse bias characteristics of the diode.
  
Go back to '''CircuitJs''' simulator.
+
Go back to the '''CircuitJs''' simulator.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
 
|| Let us first set the variable voltage value to 0 volts using the slider.
 
|| Let us first set the variable voltage value to 0 volts using the slider.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| CircuitJS Explanation
 
|| CircuitJS Explanation
 
|| Click on the '''RUN/Stop''' button on the top right corner to stop the simulation.
 
|| Click on the '''RUN/Stop''' button on the top right corner to stop the simulation.
  
 
Click on the '''Reset''' button to erase the forward bias V-I characteristics graph.
 
Click on the '''Reset''' button to erase the forward bias V-I characteristics graph.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
 
|| Let us change the circuit for Reverse bias mode.
 
|| Let us change the circuit for Reverse bias mode.
Line 246: Line 242:
 
The positive end of the supply is now connected to the cathode of the diode.
 
The positive end of the supply is now connected to the cathode of the diode.
  
And the negative end is connected to the anode of the diode.
+
The negative end is connected to the anode of the diode.
  
 
A reverse bias diode circuit is ready.
 
A reverse bias diode circuit is ready.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
||  
+
|| click on the '''RUN/Stop''' button
 
|| Now, start the simulation by clicking on the '''RUN/Stop''' button again.
 
|| Now, start the simulation by clicking on the '''RUN/Stop''' button again.
  
 
Since voltage is not applied to the circuit, current cannot pass through the circuit.
 
Since voltage is not applied to the circuit, current cannot pass through the circuit.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| '''RB_Observation Table.png'''
 
|| '''RB_Observation Table.png'''
  
Line 265: Line 261:
  
 
Since the diode is connected in reverse bias, the voltage and current readings will be negative.
 
Since the diode is connected in reverse bias, the voltage and current readings will be negative.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
 
||
+
 
||
+
|-  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
 
|| '''Show dot in the graph'''
 
|| '''Show dot in the graph'''
 
|| For all voltage values, the current flowing through the diode is negligible.
 
|| For all voltage values, the current flowing through the diode is negligible.
  
Notice the dot on the graph, it moves along the negative x-axis.
+
Notice the dot on the graph, which moves along the negative x-axis.
  
 
This indicates that there is no change in the current flowing through the diode.
 
This indicates that there is no change in the current flowing through the diode.
 
|-
 
|-
| style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;" | Slide:
+
||Slide:
  
 
Diode Characteristics
 
Diode Characteristics
  
| style="border:1pt solid #000000;padding:0.176cm;" | Thus we can conclude the following;
+
||Thus we can conclude the following;
  
# <div style="margin-left:1.27cm;margin-right:0cm;">Forward bias in a diode allows current flow, enabling conduction.</div>
+
# Forward bias in a diode allows current flow, enabling conduction.
# <div style="margin-left:1.27cm;margin-right:0cm;">Reverse bias creates a barrier, limiting a negligible current passing through the diode</div>
+
# Reverse bias creates a barrier, limiting a negligible current passing through the diode
  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
||  
 
||  
 
|| This brings us to the end of the tutorial. Let us summarize.
 
|| This brings us to the end of the tutorial. Let us summarize.
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Slide Summary  
 
|| Slide Summary  
 
|| In this tutorial, we learnt about
 
|| In this tutorial, we learnt about
  
* <div style="margin-left:1.27cm;margin-right:0cm;">Voltage-current(V-I), characteristics of Silicon diode in forward and reverse bias</div>
+
* Voltage-current(V-I), characteristics of Silicon diode in forward and reverse bias
  
|- style="border:1pt solid #000000;padding:0.176cm;"
+
|-  
 
|| Slide:
 
|| Slide:
  
 
Assignment
 
Assignment
 
|| As an assignment,
 
|| As an assignment,
* <div style="margin-left:1.27cm;margin-right:0cm;">Find the knee voltage of the '''Germanium''' diode.</div>
+
* Find the knee voltage of the '''Germanium''' diode.
  
 
Hint - Double click on the diode and select 1N34 (germanium diode).
 
Hint - Double click on the diode and select 1N34 (germanium diode).
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| Slide :
 
|| Slide :
  
Line 309: Line 304:
  
 
Please download and watch it.
 
Please download and watch it.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| Slide&nbsp;:Spoken Tutorial workshops
 
|| Slide&nbsp;:Spoken Tutorial workshops
 
|| The&nbsp;Spoken Tutorial Project&nbsp;Team conducts workshops and gives certificates.
 
|| The&nbsp;Spoken Tutorial Project&nbsp;Team conducts workshops and gives certificates.
  
 
For more details, please write to us.
 
For more details, please write to us.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| Slide : Forum for specific questions
 
|| Slide : Forum for specific questions
 
|| Please post your timed queries in this forum.
 
|| Please post your timed queries in this forum.
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| Acknowledgement
 
|| Acknowledgement
 
|| Spoken Tutorial project was established by the Ministry of Education(MoE), Govt of India
 
|| Spoken Tutorial project was established by the Ministry of Education(MoE), Govt of India
|- style="border:1pt solid #000000;padding-top:0cm;padding-bottom:0cm;padding-left:0.206cm;padding-right:0.191cm;"
+
|-  
 
|| Thank you
 
|| Thank you
 
|| This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.
 
|| This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.
  
Thanks for watching.
+
Thank you for watching.
 
|-
 
|-
 
|}
 
|}

Revision as of 17:47, 26 April 2024

Visual Cue Narration
slide:1 Welcome to the spoken tutorial on Silicon Diode Characteristics using CircuitJS simulator.
Slide 2:

Learning Objective

In this tutorial, we will learn about
  • Voltage-Current(V-I) characteristics of Silicon diode in forward and reverse bias.
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
Slide 5:

What is a Diode?

  • Diode is a semiconductor device with two terminals.
  • These terminals control the flow of electrons in a circuit.
  • Diodes can be used as rectifiers, switches, voltage regulators etc.
Slide 6:

Diode image

Diode_Symbol.png

  • Diode is represented with this symbol.
  • The diode symbol has a triangle with a line across one vertex.
  • The vertex side of the triangle is cathode.
  • The base side of the triangle is an anode of the diode.
Slide:

Diode Biasing

The process of applying an external voltage to a p-n junction of a diode is called biasing.

There are two ways of Biasing:

  1. Forward Bias and
  2. Reverse Bias
Forward Bias

Forward_Bias_Diode.png

In forward bias,
  • The positive terminal of the power supply is connected to the P-Junction or anode of the diode
  • The negative terminal of the power supply is connected to the N-junction or cathode of the diode
Show the circuit diagram We will make this circuit to explain forward bias characteristics of the diode.
Show the diagram

Forward_Bias_Diode.png

For Forward bias diode circuit, we require,
  • Variable voltage (That is, 0 volts to 2 volts)
  • Diode
  • Ammeter
  • 1 Ohm resistor
  • Ground
Keep the circuit diagram on top right Let us open the CircuitJS interface.

In the menu bar, click on File and select New Blank Circuit.

Select variable voltage Click on Draw, go to Inputs and Sources, and select Add Variable voltage.

Draw the variable voltage in the working area as shown.

We require a voltage range of 0 to 2 volts.

Right click on the variable voltage component and select the Edit option.

In the Minimum voltage box, enter 0 and in the maximum voltage box, enter 2.

Click on the OK button to save the changes.

Select Diode Click on Draw, go to Active Components, and select Add Diode option.

Draw the diode in the working area.

This is the default diode available on the CircuitJS platform.

This diode has characteristics of a Silicon diode.

Connect the P-junction of the diode to the variable voltage in the circuit.

Select Ammeter Now, click on Draw, go to Outputs and Labels, and select Add Ammeter component.

Draw the ammeter in the working area as shown.

Connect the ammeter to the N-junction of the diode.

Next, we will connect a resistor to the ammeter.

Select Resistor Go to Draw, select Add resistor option.

Drag and draw the resistor in the working area as shown.

The default value of the resistor is 1 Kilo Ohm.

Use the Edit option and change the resistor value to 1 Ohm.

Select Ground Now, we need a ground component to complete the circuit.

Click on Draw, go to Inputs and Sources and select Add ground option.

Draw and connect the ground component to the resistor in the circuit as shown.

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

On the right side, you will see a slider to change the voltage value.

Use the slider to change the variable voltage value to 0 volts as shown.

We need a graph with relevant values of voltage and current.

These values will explain the V-I characteristics of a silicon diode.

Select View in New Scope and open graph

Go to settings

Right click on the diode and select View in New Scope option.

A graph will appear at the bottom of your screen.

Increase the size of the graph by dragging the graph screen.

At the bottom left corner, you will see a Settings icon, click on it.

Change the graph A pop-window will open.

Click on the X-Y Plot option, check the Show V vs I box.

Click on the OK button to save the changes.

The voltage values are plotted on the X-axis represented by the green line.

The current values are plotted on the Y-axis represented by the yellow line.

FB_Observation Table.png Create a table to note down the current readings for the given voltage values.
FB_0 volts.png

Silicon_Diode Video.mp4 (do not include from 6.38 to 8.06)

At 0 volts, the ammeter shows no current flowing through the diode.

Hence, the current value for this condition is 0 Ampere.

Notice the dot in the graph, it shows the voltage and current values.

Editing

Put a red box around the changes in values

FB_0.5 volts.png

Now, we will gradually increase the variable voltage using the voltage slider.

Note the changes in voltage and current in the circuit.

For voltage value 0.5 volts, the ammeter shows negligible current flow through the diode.

We can see the dot on the graph moving along the x-axis.

FB_0.7 volts.png As we increase the voltage value to 0.7 volts, the ammeter shows an increase in the current value.

The dot in the graph moves on the Y axis which shows increase in current.

This point where the current increases is called the knee voltage.

Thus, the knee voltage for the silicon diode is 0.7 volts.

Move the slider the slowly

FB_2 volts.png

Note down the current reading for the remaining voltage values of 1 volt, 1.5 volts and 2 volts.

Notice the dot in the graph showing an increase in the current value.

Hence for input voltage above 0.7 volts, the silicon diode acts as a conductor.

Let us now see how a diode behaves in reverse bias mode.
Slide:

Reverse_Bias_Diode.png

In reverse bias,
  1. The positive terminal of the power supply is connected to the N-Junction or cathode of the diode;
  2. The negative terminal of the power supply is connected to the P-junction or anode of the diode;
Reverse_Bias_Diode.png We will create this circuit to explain reverse bias characteristics of the diode.

Go back to the CircuitJs simulator.

Let us first set the variable voltage value to 0 volts using the slider.
CircuitJS Explanation Click on the RUN/Stop button on the top right corner to stop the simulation.

Click on the Reset button to erase the forward bias V-I characteristics graph.

Let us change the circuit for Reverse bias mode.

Right click on the diode and select the Swap Terminals option.

The positive end of the supply is now connected to the cathode of the diode.

The negative end is connected to the anode of the diode.

A reverse bias diode circuit is ready.

click on the RUN/Stop button Now, start the simulation by clicking on the RUN/Stop button again.

Since voltage is not applied to the circuit, current cannot pass through the circuit.

RB_Observation Table.png

Editing

Red box around the negative value

Let us increase the variable voltage from 0 volts to 2 volts using the slider.

Refer to the observation table for the diode connected in reverse bias mode.

Since the diode is connected in reverse bias, the voltage and current readings will be negative.


Show dot in the graph For all voltage values, the current flowing through the diode is negligible.

Notice the dot on the graph, which moves along the negative x-axis.

This indicates that there is no change in the current flowing through the diode.

Slide:

Diode Characteristics

Thus we can conclude the following;
  1. Forward bias in a diode allows current flow, enabling conduction.
  2. Reverse bias creates a barrier, limiting a negligible current passing through the diode
This brings us to the end of the tutorial. Let us summarize.
Slide Summary In this tutorial, we learnt about
  • Voltage-current(V-I), characteristics of Silicon diode in forward and reverse bias
Slide:

Assignment

As an assignment,
  • Find the knee voltage of the Germanium diode.

Hint - Double click on the diode and select 1N34 (germanium diode).

Slide :

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Thank you This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.

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Contributors and Content Editors

Madhurig, Nirmala Venkat