RC Time Constant
Also known as tau = RC · capacitor charging time
Enter your known values, leave one input blank, and solves for the missing one. Try different units for next level excitement!
Learning zone
Ohms times farads gives seconds — a neat dimensional accident with real meaning: τ is the time for an RC circuit to charge or discharge about 63% of the way (a factor of 1 − 1/e). After 5τ the capacitor is over 99% there, effectively done. A 10 kΩ resistor with a 100 µF capacitor gives τ = 1 s, an easy timing element for blinkers and delay circuits.
RC Time Constant
Where
- = Time constant
- = Resistance
- = Capacitance
Missing one of these? Work it out first, then come back
- Time constant — RC Capacitor Discharge, RL Time Constant (τ = L/R)
- Resistance — Ohm's Law, Electrical Power (P = I²R)
- Capacitance — Capacitance (C = Q/V), Energy Stored in a Capacitor