RC time constant and RLC circuit calculator

RC and RL time constant and the time to charge or discharge to any percent; series RLC resonant frequency, impedance, phase, Q factor and bandwidth.

Diperbarui Contoh terverifikasi: 7

Accepts 4.7k
V
%
Percent of the final value (charging) or of the starting value (discharging)
Opsi lainnya
Auto picks s, ms, µs or ns from the size of τ
Coba
Time constant τ
s
Time constant τ: 1 s
Angka penting: 6; Terdekat, jika berjarak sama menjauhi nol
Time to reach the level
2.30259s
Final value
5V
Energy stored when fully charged
0.00125J

τ = 1 s: after one τ the capacitor voltage has risen to 63.2% of 5 V, and it takes 2.303 s to reach 90%. After 5τ it is within 1% of the final value.

Capacitor voltage over five time constants

01234012345Time (s)Capacitor voltage (V)1τ: 63.2%90% at 2.303 s
Cara menghitung S
  1. Time constant

    τ=RC=(10,000)(0.0001)=1 s\tau = RC = (10{,}000)(0.0001) = 1\ \mathrm{s}
  2. Rise towards the final value

    x(t)=X∞(1−e−t/τ),X∞=5 Vx(t) = X_\infty\left(1 - e^{-t/\tau}\right),\quad X_\infty = 5\ \mathrm{V}
  3. Time to reach 90%

    t=−τln⁡(1−0.9)=2.30259 st = -\tau\ln(1 - 0.9) = 2.30259\ \mathrm{s}
  4. Stored energy when fully charged

    E=12CV2=0.00125 JE = \tfrac12 CV^2 = 0.00125\ \mathrm{J}

Tentang RC time constant and RLC circuit calculator

An RC circuit responds with time constant τ = RC and an RL circuit with τ = L/R: after one τ the capacitor voltage or inductor current has covered 63.2% of the way to its final value, and reaching a fraction p takes t = −τ ln(1 − p). For a series RLC circuit the calculator finds the resonant frequency f₀ = 1/(2π√(LC)), the impedance and phase at your signal frequency from the reactances 2πfL and 1/(2πfC), and Q = (1/R)√(L/C).

The default, 10 kΩ with 100 µF on a 5 V supply, gives τ = 1 s and 2.30 s to reach 90%. RC time constants set timer delays, switch debounce periods and filter cut-off frequencies, 1/(2πRC). With 10 Ω, 10 mH and 1 µF in series, f₀ = 1,591.55 Hz and Q = 10.

Components are ideal and the input is a step: no capacitor leakage and no inductor winding resistance beyond R. After 5τ the response is within 0.67% of its final value (e⁻⁵), the usual rule for "fully charged".

Contoh penyelesaian

10 kΩ and 100 µF charging to 90%

Circuit
RC
Resistance R
10
Resistance unit
kΩ
Capacitance C
100
Capacitance unit
µF
Process
Charging / rising
Source voltage
5 V
Time to reach this level
90%
Time constant τ
1 s
Time to reach the level
2.30259 s
Energy stored when fully charged
0.00125 J

Sumber pemeriksaan: Python 3.8 math: τ = 10⁴ × 10⁻⁴ = 1 s; t = τ ln 10; E = ½CV² = ½·10⁻⁴·25

Capacitor voltage after one τ

Circuit
RC
Resistance R
10
Resistance unit
kΩ
Capacitance C
100
Capacitance unit
µF
Process
Charging / rising
Source voltage
5 V
Time to reach this level
90%
Value at time
1 s
Value at the chosen time
3.1606 V

Sumber pemeriksaan: Python 3.8 math: 5(1 − e⁻¹) = 3.1606028

Discharging to half: t = τ ln 2

Circuit
RC
Resistance R
10
Resistance unit
kΩ
Capacitance C
100
Capacitance unit
µF
Process
Discharging / decaying
Source voltage
5 V
Time to reach this level
50%
Time to reach the level
0.693147 s

Sumber pemeriksaan: Python 3.8 math: ln 2 = 0.6931472 (τ = 1 s)

RL: 100 Ω and 10 mH

Circuit
RL
Resistance R
100
Resistance unit
Ω
Inductance L
10
Inductance unit
mH
Process
Charging / rising
Source voltage
5 V
Time to reach this level
90%
Show times in
s
Value at time
50 µs
Time constant τ
0.0001 s
Final value
0.05 A
Value at the chosen time
0.019673 A

Sumber pemeriksaan: Python 3.8 math: τ = L/R = 10⁻⁴ s, I = 5/100, i(50 µs) = 0.05(1 − e^−0.5) = 0.0196735

Pertanyaan

What is the RC time constant?

τ = R × C, in seconds when R is in ohms and C in farads. It is the time a charging capacitor takes to reach 63.2% (1 − e⁻¹) of the supply voltage, or a discharging one to fall to 36.8%. 10 kΩ with 100 µF gives τ = 1 s; 1 kΩ with 1 µF gives 1 ms.

How long does it take a capacitor to fully charge?

About five time constants. After 5τ the voltage is 99.33% of the supply (1 − e⁻⁵), which engineers treat as fully charged; in theory it never quite gets there. Reaching 90% takes τ ln 10 ≈ 2.303τ and 99% takes τ ln 100 ≈ 4.605τ, so a 10 kΩ, 100 µF circuit reaches 99% in 4.6 s.

How do you calculate the resonant frequency of an RLC circuit?

f₀ = 1/(2π√(LC)), with L in henries and C in farads; in a series circuit R does not shift it. 10 mH with 1 µF resonates at 1,591.55 Hz, and 100 µH with 100 pF at 1.59 MHz. At f₀ the inductive and capacitive reactances are equal and cancel, so the impedance falls to R alone and the current peaks.

What is the Q factor of a series RLC circuit?

Q = (1/R)√(L/C), the ratio of either reactance at resonance to the resistance. It sets the −3 dB bandwidth, Δf = f₀/Q: 10 Ω, 10 mH and 1 µF give Q = 10 and a 159 Hz band around 1,592 Hz. Above Q = 0.5 the circuit rings (underdamped); exactly 0.5 is critically damped, reached here at R = 2√(L/C) = 200 Ω.

What is the time constant of an RL circuit?

τ = L/R. It is the time for the current to rise to 63.2% of its final value V/R after the switch closes, or to fall to 36.8% once the source is removed and the coil discharges through R. 10 mH with 100 Ω gives τ = 100 µs, so on 5 V the current reaches 99% of 50 mA in about 460 µs.

Seberapa akurat “RC time constant and RLC circuit calculator”?

Akurasi bergantung pada masukan dan asumsi metode. Aritmetika desimal memakai 50 digit signifikan, tetapi perkiraan, metode numerik dan data sumber bisa kurang presisi; pembulatan yang ditampilkan tidak menghilangkan batasan itu. Contoh penyelesaian yang diperiksa dengan sumber independen: 7. Misalnya, “10 kΩ and 100 µF charging to 90%” diperiksa dengan Python 3.8 math: τ = 10⁴ × 10⁻⁴ = 1 s; t = τ ln 10; E = ½CV² = ½·10⁻⁴·25.

Dari mana metode ini berasal?

OpenStax University Physics Volume 2, §10.5 RC circuits; §14.4 RL circuits; §15.3 RLC series circuits with AC; HyperPhysics — Series RLC resonance and Q.

Tentang kalkulator ini

τRC=RC, τRL=LR,v(t)=V(1−e−t/τ);f0=12πLC, ∣Z∣=R2+(XL−XC)2, Q=1RLC\tau_{RC} = RC,\ \tau_{RL} = \frac{L}{R},\quad v(t) = V(1 - e^{-t/\tau});\qquad f_0 = \frac{1}{2\pi\sqrt{LC}},\ |Z| = \sqrt{R^2 + (X_L - X_C)^2},\ Q = \frac1R\sqrt{\frac{L}{C}}

Sumber

  1. OpenStax University Physics Volume 2, §10.5 RC circuits; §14.4 RL circuits; §15.3 RLC series circuits with AC
  2. HyperPhysics — Series RLC resonance and Q

Diperiksa dengan referensi

Kalkulator ini mencakup 7 contoh perhitungan dengan jawaban dari sumber independen. Contoh tersebut dijalankan dalam rangkaian pengujian dan dapat Anda jalankan di sini juga.

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