1. What is the RC Discharge Equation?

The RC discharge equation describes how voltage decays in a resistor-capacitor circuit over time. It's fundamental in electronics for timing circuits, filters, and signal processing applications.

2. How Does the Calculator Work?

The calculator uses the RC discharge equation:

Where:

• \( V \) — Voltage at time t (V)
• \( V_0 \) — Initial voltage (V)
• \( t \) — Time since discharge began (s)
• \( \tau \) — Time constant = R × C (s)

Explanation: The equation shows exponential decay where voltage drops to about 37% of its initial value after one time constant (τ).

3. Importance of RC Time Constant

Details: The time constant (τ) determines how quickly the capacitor discharges. A larger τ means slower discharge. After 5τ, the voltage is considered fully discharged (~0.7% of V₀).

4. Using the Calculator

Tips: Enter initial voltage in volts, time in seconds, and time constant in seconds. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is the time constant (τ) in an RC circuit?
A: The time constant is the product of resistance (R) and capacitance (C) in the circuit (τ = R×C). It determines the discharge rate.

Q2: How do I calculate τ if I know R and C?
A: Simply multiply the resistance (in ohms) by the capacitance (in farads). For example, 1kΩ × 1μF = 1ms.

Q3: What percentage of voltage remains after one time constant?
A: After one τ, the voltage is about 36.8% of V₀ (exactly 1/e of the initial voltage).

Q4: Can this equation be used for charging as well?
A: The charging equation is similar but inverted: V = V₀(1 - e^(-t/τ)). This calculator is for discharge only.

Q5: What are practical applications of RC discharge?
A: Used in camera flashes, timing circuits, analog filters, power supply smoothing, and many other electronic applications.