CircuitJS/C3/Zener-Diode-Characteristics/English
| Visual Cue | Narration |
| slide:1
Title Slide |
Welcome to the spoken tutorial on Zener Diode Characteristics using CircuitJS simulator. |
| Slide 2:
Learning Objective |
In this tutorial, we will learn about
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| Slide 4:
System Requirement |
To record this tutorial, I am using:
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| Slide 3:
Prerequisite |
To follow this tutorial, you should have a basic knowledge of,
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| Slide 5:
Zener Diode |
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| Zener_Diode_Symbol.png | A Zener diode is represented with this symbol. |
| Zener_Forward_Bias.png | We will make this circuit to explain Forward bias characteristics of the zener diode. |
| Show the diagram | For forward bias Zener Diode circuit, we require,
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| 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 12 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 12. Click on the OK button to save the changes. |
| Select Zener Diode | Click on Draw, go to Active Components, and select Add Zener Diode option.
Draw the zener diode in the working area. Connect the P-junction of the zener 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 zener diode. Now, 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 as shown. Observe the yellow dots indicating the current flow in the circuit. |
| Point to Voltage slider. | 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 zener diode. | |
| Select View in New Scope and open graph
Go to settings |
Right click on the zener 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 up window will open.
Click on the X-Y Plot option, and 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_0 volts.png | Create a table to note down the current readings for the given voltage values.
At 0 volts, the ammeter shows no current flowing through the zener diode. Hence, the current value for this condition is 0 Ampere. Notice the dot in the graph, which shows the voltage and current values. |
| FB_2 volts.png | Now, we will gradually increase the variable voltage using the voltage slider.
Note the changes in the voltage and current in the circuit. For 2 volts, the ammeter shows 1.2 Ampere current flowing through the diode. The current increases in the exponential manner. This voltage is called the knee voltage of this zener diode. |
| A zener diode's knee voltage can vary from a few volts to several hundred volts. | |
| FB_5 volts.png | Change the variable voltage value to 5 volts using the slider.
The current flowing through the diode is 4.1 Ampere. Note down these readings in the observation table. |
| FB_12 volts.png | Use the slider to change the input voltage value to 12 volts.
The ammeter shows a current flow of 11 Amperes through the zener diode. Notice the dot in the graph showing an increase in the current reading. |
| Now let us see how a zener diode behaves in reverse bias mode. | |
| Zener_Reverse_Bias.png | We will create this circuit to see the reverse bias characteristics of the zener diode.
Go back to the CircuitJS simulator. |
| Drag the voltage slider. | Let us first set the variable voltage value to 0 volts using the slider. |
| Click on the RUN/Stop button. | 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. |
| Right click on the zener diode >>
select the Swap Terminal option. |
Let us change the circuit for Reverse bias mode.
Right click on the zener diode and select the Swap Terminal option. 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. A reverse bias zener diode circuit is ready. |
| Click 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_3 volts.png | Let us increase the variable voltage from 0 volts to 3 volts.
The current flowing through the zener is negligible. It is 171 nano ampere. Note down the current value for the given variable voltage value. Notice the dot in the graph, which shows the voltage and current values. |
| RB_6.4 volts.png | Use the variable voltage slider to change the input voltage value to 6.4 volts.
Notice the current reading for voltage 6.4 in the circuit. The current reading across the ammeter shows 634 milli Amperes. You can notice the current reading in the graph increasing exponentially. This voltage is called the Breakdown voltage of the zener diode. |
| RB_12 volts.png | Use the slider to change the variable voltage value to 12 volts.
The current flowing through the zener diode is 6.2 Amperes. The current across the ammeter increases if we increase the voltage using a slider. To conclude, a zener diode is an important component in electronic circuits. It offers voltage regulation and protection of components. |
| Slide:
Silicon-Zener Diode comparison |
Let us compare the silicon and zener diode characteristics.
It will help us to determine their suitability for specific tasks.
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| This brings us to the end of the tutorial.
Let us summarize. | |
| Slide Summary | In this tutorial, we learnt about
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| Slide :
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| Thank you | This tutorial has been contributed by FOSSEE and Spoken Tutorial Project, IIT Bombay.
Thanks for watching. |
