Electric Calculator

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Electric Calculator: Ohm's Law & Power Law

function calculateElectric() { var voltageStr = document.getElementById('voltageInput').value; var currentStr = document.getElementById('currentInput').value; var resistanceStr = document.getElementById('resistanceInput').value; var powerStr = document.getElementById('powerInput').value; var V = parseFloat(voltageStr); var I = parseFloat(currentStr); var R = parseFloat(resistanceStr); var P = parseFloat(powerStr); var inputs = []; if (!isNaN(V)) inputs.push({ type: 'V', value: V }); if (!isNaN(I)) inputs.push({ type: 'I', value: I }); if (!isNaN(R)) inputs.push({ type: 'R', value: R }); if (!isNaN(P)) inputs.push({ type: 'P', value: P }); var resultDiv = document.getElementById('electricResult'); resultDiv.innerHTML = "; // Clear previous results if (inputs.length !== 2) { resultDiv.innerHTML = 'Please enter exactly two values to calculate the others.'; return; } var known1 = inputs[0]; var known2 = inputs[1]; var calculatedV, calculatedI, calculatedR, calculatedP; var error = false; // Determine which two values are known and calculate the others if ((known1.type === 'V' && known2.type === 'I') || (known1.type === 'I' && known2.type === 'V')) { V = known1.type === 'V' ? known1.value : known2.value; I = known1.type === 'I' ? known1.value : known2.value; if (I === 0) { error = true; resultDiv.innerHTML = 'Current cannot be zero when calculating resistance.'; } else { calculatedR = V / I; calculatedP = V * I; } } else if ((known1.type === 'V' && known2.type === 'R') || (known1.type === 'R' && known2.type === 'V')) { V = known1.type === 'V' ? known1.value : known2.value; R = known1.type === 'R' ? known1.value : known2.value; if (R === 0) { error = true; resultDiv.innerHTML = 'Resistance cannot be zero when calculating current or power.'; } else { calculatedI = V / R; calculatedP = (V * V) / R; } } else if ((known1.type === 'V' && known2.type === 'P') || (known1.type === 'P' && known2.type === 'V')) { V = known1.type === 'V' ? known1.value : known2.value; P = known1.type === 'P' ? known1.value : known2.value; if (V === 0) { error = true; resultDiv.innerHTML = 'Voltage cannot be zero when calculating current or resistance.'; } else { calculatedI = P / V; calculatedR = (V * V) / P; } } else if ((known1.type === 'I' && known2.type === 'R') || (known1.type === 'R' && known2.type === 'I')) { I = known1.type === 'I' ? known1.value : known2.value; R = known1.type === 'R' ? known1.value : known2.value; calculatedV = I * R; calculatedP = (I * I) * R; } else if ((known1.type === 'I' && known2.type === 'P') || (known1.type === 'P' && known2.type === 'I')) { I = known1.type === 'I' ? known1.value : known2.value; P = known1.type === 'P' ? known1.value : known2.value; if (I === 0) { error = true; resultDiv.innerHTML = 'Current cannot be zero when calculating voltage or resistance.'; } else { calculatedV = P / I; calculatedR = P / (I * I); } } else if ((known1.type === 'R' && known2.type === 'P') || (known1.type === 'P' && known2.type === 'R')) { R = known1.type === 'R' ? known1.value : known2.value; P = known1.type === 'P' ? known1.value : known2.value; if (R === 0) { error = true; resultDiv.innerHTML = 'Resistance cannot be zero when calculating voltage or current.'; } else if (P < 0) { error = true; resultDiv.innerHTML = 'Power cannot be negative for these calculations.'; } else { calculatedV = Math.sqrt(P * R); calculatedI = Math.sqrt(P / R); } } if (!error) { var outputHTML = '

Calculated Values:

'; outputHTML += 'Voltage (V): ' + (isNaN(V) ? calculatedV.toFixed(3) : V.toFixed(3)) + ' Volts'; outputHTML += 'Current (I): ' + (isNaN(I) ? calculatedI.toFixed(3) : I.toFixed(3)) + ' Amps'; outputHTML += 'Resistance (R): ' + (isNaN(R) ? calculatedR.toFixed(3) : R.toFixed(3)) + ' Ohms'; outputHTML += 'Power (P): ' + (isNaN(P) ? calculatedP.toFixed(3) : P.toFixed(3)) + ' Watts'; resultDiv.innerHTML = outputHTML; } } .calculator-container { font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; background-color: #f9f9f9; border: 1px solid #ddd; border-radius: 8px; padding: 25px; max-width: 600px; margin: 30px auto; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08); } .calculator-container h2 { color: #333; text-align: center; margin-bottom: 25px; font-size: 1.8em; } .calculator-content { display: flex; flex-direction: column; gap: 15px; } .input-group { display: flex; flex-direction: column; } .input-group label { margin-bottom: 7px; color: #555; font-size: 1em; font-weight: bold; } .input-group input[type="number"] { padding: 12px; border: 1px solid #ccc; border-radius: 5px; font-size: 1.1em; width: 100%; box-sizing: border-box; transition: border-color 0.3s ease; } .input-group input[type="number"]:focus { border-color: #007bff; outline: none; box-shadow: 0 0 5px rgba(0, 123, 255, 0.3); } button { background-color: #007bff; color: white; padding: 14px 25px; border: none; border-radius: 5px; cursor: pointer; font-size: 1.1em; margin-top: 20px; transition: background-color 0.3s ease, transform 0.2s ease; align-self: center; width: auto; } button:hover { background-color: #0056b3; transform: translateY(-2px); } .result-area { background-color: #e9f7ff; border: 1px solid #b3e0ff; border-radius: 8px; padding: 20px; margin-top: 25px; font-size: 1.1em; color: #333; line-height: 1.6; } .result-area h3 { color: #0056b3; margin-top: 0; margin-bottom: 15px; font-size: 1.4em; } .result-area p { margin-bottom: 8px; } .result-area p strong { color: #003d7a; }

Understanding Basic Electrical Principles with the Electric Calculator

Electricity is fundamental to modern life, powering everything from our homes to complex industrial machinery. Understanding its basic principles—Voltage, Current, Resistance, and Power—is crucial for anyone working with electronics, designing circuits, or simply trying to comprehend how their devices function. This Electric Calculator is designed to help you quickly determine any two unknown electrical quantities when you know the other two, based on Ohm's Law and the Power Law.

What are Voltage, Current, Resistance, and Power?

  • Voltage (V): Often described as electrical pressure, voltage is the potential difference in charge between two points in an electrical field. It's the "push" that causes electrons to move. Measured in Volts (V).
  • Current (I): This is the flow rate of electric charge (electrons) through a conductor. Think of it as the volume of water flowing through a pipe. Measured in Amperes (A), or Amps.
  • Resistance (R): Resistance is the opposition to the flow of electric current. It's like the narrowness of a pipe that restricts water flow. Materials with high resistance are insulators, while those with low resistance are conductors. Measured in Ohms (Ω).
  • Power (P): Electrical power is the rate at which electrical energy is converted into another form of energy (like heat, light, or mechanical work). It's how much "work" electricity is doing. Measured in Watts (W).

Ohm's Law: The Foundation of Electrical Circuits

Ohm's Law describes the relationship between voltage, current, and resistance. It states that the current flowing through a conductor between two points is directly proportional to the voltage across the two points and inversely proportional to the resistance between them. Mathematically, it's expressed as:

V = I × R

  • If you know Voltage (V) and Current (I), you can find Resistance (R): R = V / I
  • If you know Current (I) and Resistance (R), you can find Voltage (V): V = I × R
  • If you know Voltage (V) and Resistance (R), you can find Current (I): I = V / R

The Power Law: Calculating Electrical Work

The Power Law relates power to voltage and current. It tells us how much energy is being consumed or produced in a circuit. The most common form is:

P = V × I

By combining Ohm's Law with the Power Law, we can derive other useful formulas:

  • If you know Current (I) and Resistance (R), you can find Power (P): P = I² × R (since V = I × R, substitute V into P = V × I)
  • If you know Voltage (V) and Resistance (R), you can find Power (P): P = V² / R (since I = V / R, substitute I into P = V × I)

How to Use the Electric Calculator

Our Electric Calculator simplifies these complex relationships. To use it:

  1. Identify Your Knowns: Determine which two of the four electrical quantities (Voltage, Current, Resistance, Power) you already know.
  2. Enter Values: Input these two known values into their respective fields in the calculator. Leave the other two fields blank.
  3. Calculate: Click the "Calculate" button.
  4. View Results: The calculator will instantly display the values for the two unknown quantities, along with the original inputs, providing a complete picture of your circuit's parameters.

Practical Examples:

Let's look at some real-world scenarios where this calculator comes in handy:

Example 1: Calculating Power of an Appliance

You have a household appliance that operates on a standard 120 Volts (V) and draws 10 Amps (A) of current. What is its power consumption?

  • Enter Voltage: 120
  • Enter Current: 10
  • The calculator will show: Power (P) = 1200 Watts (W), Resistance (R) = 12 Ohms (Ω).

Example 2: Finding Current Through a Resistor

A circuit has a 24 Volt (V) power supply and a resistor with 4 Ohms (Ω) of resistance. How much current flows through the resistor?

  • Enter Voltage: 24
  • Enter Resistance: 4
  • The calculator will show: Current (I) = 6 Amps (A), Power (P) = 144 Watts (W).

Example 3: Determining Resistance of a Heating Element

A heating element is rated at 1500 Watts (W) and operates on a 240 Volt (V) supply. What is its resistance?

  • Enter Power: 1500
  • Enter Voltage: 240
  • The calculator will show: Resistance (R) = 38.4 Ohms (Ω), Current (I) = 6.25 Amps (A).

This Electric Calculator is an invaluable tool for students, hobbyists, and professionals alike, providing quick and accurate calculations for fundamental electrical parameters.

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