1. What is a Capacitor Discharge Calculator?

Definition: This calculator determines the remaining voltage across a capacitor after a specified time of discharging through a resistor.

Purpose: It helps electronics engineers, technicians, and hobbyists analyze RC circuits and timing applications.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( V \) — Voltage at time t (volts)
• \( V_0 \) — Initial voltage (volts)
• \( t \) — Time since discharge began (seconds)
• \( R \) — Resistance (ohms)
• \( C \) — Capacitance (farads)

Explanation: The voltage decays exponentially with time, where the rate depends on the RC time constant (τ = RC).

3. Importance of Capacitor Discharge Calculation

Details: Understanding capacitor discharge is crucial for circuit design, power supply analysis, timing circuits, and safety considerations.

4. Using the Calculator

Tips: Enter the initial voltage, discharge time, resistance, and capacitance. All values must be positive (time can be zero).

5. Frequently Asked Questions (FAQ)

Q1: What is the RC time constant?
A: The RC time constant (τ = RC) is the time required for the voltage to decay to 36.8% of its initial value.

Q2: How long does it take for a capacitor to fully discharge?
A: In theory, a capacitor never fully discharges, but practically, it's considered discharged after 5 time constants (reaching ~0.7% of V₀).

Q3: What happens if R or C is zero?
A: The calculation becomes invalid as RC must be positive. Zero resistance would cause instantaneous discharge (short circuit).

Q4: Can I use this for charging calculations?
A: No, the charging formula is different: V = V₀(1 - e^(-t/RC)).

Q5: How do I measure capacitance in practice?
A: Use a capacitance meter or calculate it by measuring the time constant with a known resistor.