RC Oscillator Frequency
f = 1 / (2πRC)
Quick answer
This calculator solves f = 1 / (2πRC) for Frequency. With Resistance 10 kΩ, Capacitance 100 nF, the result is 0.1592 kHz. It solves in 3 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
RC oscillators use resistors and capacitors to generate periodic waveforms without inductors. The simplest forms include the phase-shift oscillator (three RC stages providing 180 degrees phase shift) and the Wien bridge oscillator (using a series-parallel RC network). The oscillation frequency is determined by the RC time constant. RC oscillators are easy to build and tune but have lower frequency stability than crystal oscillators, making them suitable for audio frequencies and non-critical timing applications. Op-amp-based Wien bridge oscillators can produce clean sine waves from a few Hz to several hundred kHz.
Variables
- f — Oscillation frequency (Hz)
- R — Resistance (Ω)
- C — Capacitance (F)
Practical Notes
The Wien bridge oscillator needs automatic gain control (AGC) to maintain stable amplitude. A classic technique uses a small incandescent lamp as a positive temperature coefficient element in the feedback network. Modern implementations use JFETs or analog multipliers for AGC. For best frequency stability, use NP0/C0G ceramic or film capacitors and metal film resistors.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| f | Frequency | kHz | Hz, kHz, MHz, GHz |
| R | Resistance | kΩ | mΩ, Ω, kΩ, MΩ |
| C | Capacitance | nF | pF, nF, µF, mF, F |
Step by step
- 1. What you know: Resistance 10 kΩ, Capacitance 100 nF
- 2. The relation: f = 1 / (2πRC)
- 3. Substitute: R = 10 kΩ, C = 100 nF
- 4. Result: Frequency = 0.1592 kHz
Worked examples
Minimum range
Given: Resistance 100 Ω, Capacitance 100 pF
Result: Frequency = 15.92 MHz
Low range
Given: Resistance 1 kΩ, Capacitance 1 nF
Result: Frequency = 0.1592 MHz
Typical
Given: Resistance 10 kΩ, Capacitance 100 nF
Result: Frequency = 0.1592 kHz
High range
Given: Resistance 100 kΩ, Capacitance 1 µF
Result: Frequency = 1.592 Hz
Maximum range
Given: Resistance 1 MΩ, Capacitance 10 µF
Result: Frequency = 0.01592 Hz
Solving for each variable
Solve for Frequency
Resistance 100 Ω, Capacitance 100 pF → 15.92 MHz
Solve for Resistance
Frequency 100 Hz, Capacitance 100 pF → 15.92 MΩ
Solve for Capacitance
Frequency 100 Hz, Resistance 100 Ω → 15.92 µF
How Frequency changes with Resistance
| Resistance (input) | Frequency (result) |
|---|---|
| 1 kΩ | 1.592 kHz |
| 2.5 kΩ | 0.6366 kHz |
| 5 kΩ | 0.3183 kHz |
| 7.5 kΩ | 0.2122 kHz |
| 10 kΩ | 0.1592 kHz |
| 15 kΩ | 106.1 Hz |
| 20 kΩ | 79.58 Hz |
| 40 kΩ | 39.79 Hz |
| 70 kΩ | 22.74 Hz |
| 100 kΩ | 15.92 Hz |
The same result in other units
| Unit | Value |
|---|---|
| Hz | 159.2 |
| kHz | 0.1592 |
| MHz | 0.0001592 |
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<p><a href="https://vbatpower.com/formulas/rc-frequency/">RC Oscillator Frequency</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate RC Oscillator Frequency?
Use f = 1 / (2πRC). With Resistance 10 kΩ, Capacitance 100 nF, Frequency works out to 0.1592 kHz.
What is the formula for RC Oscillator Frequency?
The formula is f = 1 / (2πRC). RC oscillators use resistors and capacitors to generate periodic waveforms without inductors.
How do you find Resistance when you know the other values?
Rearrange for Resistance: with Frequency 100 Hz, Capacitance 100 pF, Resistance is 15.92 MΩ.
How do you find Capacitance when you know the other values?
Rearrange for Capacitance: with Frequency 100 Hz, Resistance 100 Ω, Capacitance is 15.92 µF.
What units does RC Oscillator Frequency use?
Frequency is shown in Hz, kHz, MHz. Values are held in SI base units internally, so you can mix prefixes without converting by hand.
Related Concepts
All Timing & Oscillators formulas →Need more features?
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