Electricity & Magnetism
RC Time Constant
Time constant for RC circuit charging/discharging.
Variables
τs
Time constant
Characteristic time
Allowed values: 0 or more
RΩ
Resistance
Circuit resistance
In SI units: kg·m²/(A²·s³)
Allowed values: 0 or more
CF
Capacitance
Circuit capacitance
In SI units: A²·s⁴/(kg·m²)
Allowed values: greater than 0
Derivation
From differential equation: V(t) = V₀e^(-t/RC).
Your notes
0/5000
Check value
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- R = 2 Ω (Resistance)
- C = 3 F (Capacitance)
Result: τ = 6 s
Other electricity & magnetism formulas with the same quantities
- RL Time Constant (Electromagnetic Induction) shares Time constant, Resistance
- Parallel Plate Capacitor (Capacitance) shares Capacitance
- Capacitor Energy (Capacitance) shares Capacitance
- Capacitor with Dielectric (Capacitance) shares Capacitance
- Electric Power (Electric Circuits) shares Resistance
- Resistance (Electric Circuits) shares Resistance
Where this formula is listed
- Electricity & Magnetism formulas, under Capacitance, alongside Capacitors in Series, Capacitors in Parallel and Energy Density (Electric Field).
- In the electricity & magnetism list it comes after Capacitors in Parallel and before Capacitor with Dielectric.
- Electricity & Magnetism formula sheet, one of 48 formulas printed with symbol keys and SI units.
- The full formula index, grouped by category and topic.
Common questions
What is the RC Time Constant formula?
RC Time Constant is written τ = RC. Time constant for RC circuit charging/discharging. It belongs to Electricity & Magnetism, under Capacitance.
What are the units in τ = RC?
In SI units, τ is time constant, measured in s; R is resistance, measured in kg·m²/(A²·s³); C is capacitance, measured in A²·s⁴/(kg·m²).
How is the RC Time Constant formula derived?
From differential equation: V(t) = V₀e^(-t/RC). The result is τ = RC.