CircuitJS

CircuitJS is a free and open source application where various experiments can be performed with electronic circuits. CircuitJS is a web browser based electronic circuit simulator. It can be used online as well as in offline mode.

CircuitJS is highly interactive and lets users experiment with various circuit components like batteries, resistors, inductors, capacitors.

It is an interesting and useful tool for simulating, learning and visualizing electronic circuits. As it is an easy to use tool, it has been used to teach circuits to those who have difficulty in learning circuits.

Furthermore, CircuitJS allows you to adjust the values, orientations, and placement of these components within the circuit. A virtual environment will help you understand how voltage is divided, current flows in a circuit, and how to turn a light on and off.

The CircuitJS project was developed initially by Paul Falstad, and later by Lush Projects.

The Spoken Tutorial effort for CircuitJS has been contributed by Nirmala Venkat, Pratik Bhosale and Rajesh kushalkar from the FOSSEE team.

Learners: High School, Electronics students, and hardware professionals.

Basic Level

1. Installation of CircuitJS

• How to use CircuitJS in online mode?
• Link: https://www.falstad.com/circuit/circuitjs.html
• Default LRC Circuit
• Overview of the interface
• Sliders for simulation speed and speed of the current
• Installation of CircuitJS in Linux OS
• Download and launch in the terminal
• Java is required to run the CircuitJS
• Installation of CircuitJS in Windows OS
• Offline versions of Ubuntu and Windows resemble the online platform

2. Ohm's Law using CircuitJS simulator

• Verify Ohm's Law using CircuitJS simulator.
• Check how voltage, resistance and current are related?
• Circuit design for Ohm's Law.
• Draw the circuit with 4 DC voltage, 1 resistor, voltmeter, Ammeter and switch.
• Make duplicates of the devices and change their values.
• Add labels and arrange them.
• Make the wire connections.
• Observe the yellow dots indicating the current flow direction in the circuit.
• Observe the current reading across the Ammeter.
• Verify the Ohm's Law with other parameters.

3. Series and Parallel Resistance

• Create a series resistor circuit using CircuitJS
• Change the DC power supply from 5 volts to 12 volts
• Add Switch, Ammeter and three resistors to complete the circuit
• Duplicate and Rename the resistors
• Create a parallel resistor circuit using CircuitJS
• Change the DC power supply from 5 volts to 12 volts
• Add Switch, 4 Ammeters and three resistors to complete the circuit
• Compare the series and parallel circuits
• Example of a series connection circuit using LED
• Example of a parallel connection circuit using LED

4. Voltage Divider

• Create a Voltage divider circuit in CircuitJS simulator
• Draw the circuit with 2 Resistors,1 DC power supply and Analog Output
• Duplicate and rename the resistors
• Change the DC power supply from 5v to 12v
• Complete the circuit and observe the voltage reading at the analog output
• Use the voltage divider formula Vout = Vin (R1/R1+R2) to calculate the output voltage
• Change the resistor value and observe the change in the analog output reading
• Note the change in the analog output reading as the resistor values is changed

5. AC and DC Circuit

• Create a DC circuit in CircuitJS simulator
• Draw the circuit with 1 resistor of 10 ohms, 1 DC power supply of 5 V
• Connect the resistor and the DC power supply and observe the yellow dots in the circuit
• Observe that for the DC power supply, the conventional current flows in a single direction
• Note the waveform of current and voltage values plotted on a graph
• Create a AC circuit in CircuitJS simulator
• Draw the circuit with 1 resistor of 10 ohms, 1 AC power supply of 5 V
• Make the circuit and observe the yellow dots in the circuit
• Observe the direction of current flowing in forward and backward directions
• Note the waveform of the current in an AC circuit fluctuates forward and backward

6. LCR Circuit

• Create a LCR circuit in CircuitJS simulator
• How a resistor, capacitor and an inductor behave in the AC circuit when connected in series
• Draw the circuit with 1 resistor, 1 inductor, 1 capacitor, and 1 AC power supply
• Make the circuit with the AC power supply and observe the yellow dots in the circuit
• Place the cursor on the resistor to see its characteristics at the bottom right of the screen
• Observe the characteristics of each component in the LCR circuit with the help of graphs
• The current and voltage flowing through a resistor are in phase
• The current and voltage flowing through a capacitor are said to be out of phase
• The current is 0 when the voltage through the inductor reaches the maximum value
• Applications of LCR circuit

7. Kirchhoff's Law

• What is Kirchhoff’s Voltage Law?
• What is Kirchhoff’s Current Law?
• Create a complex circuit with 2 DC sources to verify Kirchhoff's Voltage and Current Laws
• Draw a circuit with 5 resistors of 1 Kilo Ohms and 2 DC power supply of 5 Volts in CircuitJS simulator
• Show that current I1 flows in a clockwise direction in the circuit
• Show that current I2 flows in an anti-clockwise direction in the circuit
• Note down the current flowing through various resistors
• Do the calculation and find the values of V1 and V2
• To verify Kirchhoff’s voltage law, show that the sum of all the voltages in the closed circuit is 0
• To verify Kirchhoff’s current law, show that the sum of currents entering the junction is equal to the sum of currents leaving the junction

8. Wheatstone Bridge

• About Wheatstone Bridge
• What is Balance condition of Wheatstone Bridge?
• Draw a circuit with 4 resistors, 1 DC power supply, 1 Switch and 1 ammeter in CircuitJS simulator
• Observe the yellow dots indicating the current flow direction in the circuit
• Change the value of 3 resistors to 200, 400, 400 ohms
• Keep the 4th resistor as unknown value
• Find the value of the 4th resistor with Wheatstone Bridge balanced condition formula
• The balanced condition formula is P/Q = R/S. To find S, the formula becomes S = R x Q / P
• Change the 4th resistor value in the circuitJS with the value of S
• Note the ammeter shows zero value which shows the Wheatstone Bridge is in balanced condition

Intermediate Level

1. Zener Diode Characteristics

• About Zener Diode
• Circuit design for Forward bias characteristics of the Zener diode
• Draw the circuit with variable voltage ( 0 volt to 12 volts), Zener Diode, Ammeter,1 Ohms Resistor, Ground
• Make the circuit connection in the CircuitJS interface
• Observe the yellow dots indicating the current flow in the circuit
• Invoke the graph option to see the relevant values of voltage and current
• Increase the variable voltage using the voltage slider and observe the dot in the graph
• Change the circuit for Reverse bias mode
• Notice the current reading in the graph increasing exponentially
• Observe the Breakdown voltage of the Zener diode

2. AND Gate

• About Logic gates
• Create a circuit using switches and LEDs for the AND Gate demonstration
• Make the circuit with 2 switches, 1 LED, 220 ohm resistor and DC power supply
• Draw the circuit in circuitJS interface
• Verify the working of the circuit with AND gate truth table
• Open or close the switch to indicate 0 or 1
• Use AND gate component provided by CircuitJS simulator
• Add two logic inputs pins and one logic output pin to the component
• Change the input pin's value and check the output
• Verify the AND gate truth table

3. OR Gate

• About OR Gate and how to verify the truth table
• Create a circuit using switches and LEDs for the OR Gate demonstration
• Make the circuit with 2 switches, 1 LED, 2 resistors of 220 Ohm and 1 DC power supply
• Draw the circuit in circuitJS interface
• Verify the working of the circuit with OR gate truth table
• Open or close the switch to indicate 0 or 1
• Use OR gate component provided by CircuitJS simulator
• Add two logic inputs pins and one logic output pin to the component
• Change the input pin's value and check the output
• Verify the OR gate truth table with the OR gate component

4. NOT Gate

• About NOT Gate and how to verify the truth table
• Create a circuit using switch and LED for the NOT Gate demonstration
• Make the circuit with 1 switch, 1 LED, 1 resistor of 220 Ohm and 1 DC power supply
• Draw the circuit in CircuitJS interface
• Verify the working of the circuit with NOT gate truth table
• Open or close the switch to indicate 0 or 1
• Use Add Inverter option provided by CircuitJS simulator for NOT gate demonstration
• Add one logic input pin and one logic output pin to the component
• Change the input pin's value and check the output
• Verify the NOT gate truth table with the OR gate component

5. NAND Gate

• About NAND Gate
• Create a circuit using AND gate and NOT gate for the NAND Gate demonstration
• Make the circuit with 1 AND gate, 1 NOT gate, 2 logic inputs and 1 logic output
• Draw the circuit in circuitJS interface
• Verify the working of the circuit with NAND gate truth table
• Click on the logic input to change the value from 0 to 1
• Use NAND gate component provided by CircuitJS simulator
• Add 2 logic input pins and one logic output pin to the component
• Change the input pin's value and check the output
• Verify the NAND gate truth table with the NAND gate component

6. NOR Gate

• About NOR Gate
• Create a circuit using OR gate and NOT gate for the NOR Gate demonstration
• Make the circuit with 1 OR gate, 1 NOT gate, 2 logic inputs and 1 logic output
• Draw the circuit in circuitJS interface
• Verify the working of the circuit with NOR gate truth table
• Click on the logic input to change the value from 0 to 1
• Use NOR gate component provided by CircuitJS simulator
• Add 2 logic input pins and one logic output pin to the component
• Change the input pin's value and check the output
• Verify the NOR gate truth table with the NOR gate component

Contributors and Content Editors

Madhurig