Kirchhoff's Laws with Arduino | Generated by AI

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Using an Arduino to verify Kirchhoff’s Laws—specifically Kirchhoff’s Current Law (KCL) and Kirchhoff’s Voltage Law (KVL)—is a great way to blend electronics theory with hands-on experimentation. KCL states that the total current entering a junction equals the total current leaving it, while KVL states that the sum of voltage drops around a closed loop equals the supplied voltage. Here’s how you can design simple circuits and use an Arduino to measure currents and voltages to confirm these laws.

Since Arduino can’t directly measure current, we’ll infer it by measuring voltage across resistors (using Ohm’s Law: ( I = V/R )), and it can measure voltage via its analog pins (0–5V range). Below, I’ll outline two experiments—one for KCL and one for KVL—with step-by-step instructions, wiring, and code.


Experiment 1: Verifying Kirchhoff’s Current Law (KCL)

Objective

Demonstrate that the current entering a node equals the current leaving it.

Circuit Setup

Theory

Arduino Code

void setup() {
  Serial.begin(9600); // Start serial communication
}

void loop() {
  // Read voltages (0-1023 maps to 0-5V)
  int sensorValue1 = analogRead(A0); // Voltage across R1
  int sensorValue2 = analogRead(A1); // Voltage across R2
  int sensorValue3 = analogRead(A2); // Voltage across R3

  // Convert to voltage (5V reference, 10-bit ADC)
  float V1 = sensorValue1 * (5.0 / 1023.0);
  float V2 = sensorValue2 * (5.0 / 1023.0);
  float V3 = sensorValue3 * (5.0 / 1023.0);

  // Resistor values (in ohms)
  float R1 = 330.0;
  float R2 = 470.0;
  float R3 = 680.0;

  // Calculate currents (I = V/R)
  float I1 = V1 / R1;
  float I2 = V2 / R2;
  float I3 = V3 / R3;

  // Total current entering node (assuming Vsource = 5V)
  float totalResistance = 1.0 / ((1.0/R1) + (1.0/R2) + (1.0/R3)); // Parallel
  float Iin = 5.0 / totalResistance;

  // Output results
  Serial.print("I1 (mA): "); Serial.println(I1 * 1000);
  Serial.print("I2 (mA): "); Serial.println(I2 * 1000);
  Serial.print("I3 (mA): "); Serial.println(I3 * 1000);
  Serial.print("Iin (mA): "); Serial.println(Iin * 1000);
  Serial.print("Sum of I1+I2+I3 (mA): "); Serial.println((I1 + I2 + I3) * 1000);
  Serial.println("---");

  delay(2000); // Wait 2 seconds
}

Verification


Experiment 2: Verifying Kirchhoff’s Voltage Law (KVL)

Objective

Show that the sum of voltage drops around a closed loop equals the supply voltage.

Circuit Setup

Theory

Arduino Code

void setup() {
  Serial.begin(9600);
}

void loop() {
  // Read voltages
  int sensorValueSource = analogRead(A0); // Across 5V to GND
  int sensorValueR1 = analogRead(A1);     // Across R1
  int sensorValueR2 = analogRead(A2);     // Across R2

  // Convert to voltage
  float Vsource = sensorValueSource * (5.0 / 1023.0);
  float VR1 = sensorValueR1 * (5.0 / 1023.0);
  float VR2 = sensorValueR2 * (5.0 / 1023.0);

  // Output results
  Serial.print("Vsource (V): "); Serial.println(Vsource);
  Serial.print("VR1 (V): "); Serial.println(VR1);
  Serial.print("VR2 (V): "); Serial.println(VR2);
  Serial.print("VR1 + VR2 (V): "); Serial.println(VR1 + VR2);
  Serial.println("---");

  delay(2000);
}

Verification


Tips and Considerations

These experiments simplify real-world conditions but effectively demonstrate Kirchhoff’s Laws. Want to tweak these setups or need help with a specific part (like wiring or code)? Let me know!


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