免费RC时间常数计算器

计算RC电路的时间常数τ=RC。

Ω
μF

Time Constant (τ)

1.0000 s

Time Constant (ms)1,000.00 ms
Full Charge Time (5τ)5.0000 s

Time Constant (τ) vs Resistance

公式

## RC Time Constant The time constant characterizes how quickly a capacitor charges or discharges through a resistor. ### Formula **τ = R * C** After one time constant, the capacitor reaches about 63.2% of its final value. After 5τ, it is over 99% charged.

计算示例

A 10 kΩ resistor with a 100 μF capacitor.

  1. 01τ = R * C
  2. 02τ = 10000 * 100e-6
  3. 03τ = 1.0 s
  4. 045τ = 5.0 s (99.3% charged)

常见问题

What does one time constant mean physically?

After one time constant, the voltage across the capacitor has reached 63.2% of the supply voltage during charging, or dropped to 36.8% during discharging.

Why is 5 time constants considered fully charged?

After 5τ, the capacitor has reached 99.3% of its final value. The remaining 0.7% is negligible for most applications.

Where are RC circuits used?

RC circuits are used in filters, timing circuits, smoothing power supplies, debouncing switches, and many signal processing applications.

学习

Understanding Newton's Laws of Motion

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