RC Circuit Time Constant Calculator

Calculate the time constant (τ = RC), voltage, and current at any time for an RC circuit during charging or discharging.

Resistance

Capacitance

Initial / Supply Voltage

Time

Tab to move between fields

Time Constant (τ)

0 s

Discharge Voltage at t

1.84 V

Charging Voltage at t3.16 V

Current at t0 A

Time to 37% (1τ)0 s

Time to 1% (4.6τ)0 s

How to Use This Calculator

Enter Resistance, Capacitance, and Initial / Supply Voltage.
Set Time.
Review Time Constant (τ) and Discharge Voltage at t.
Use Charging Voltage at t and Current at t (A) to inform your decision.
Use the chart to visualize the results and explore different scenarios by adjusting inputs.

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