Frequency
480.00 Hz
Duty
66.7%
Period
2.083 ms
e.g. 0.0000001 = 100nF, 0.000001 = 1µF
Frequency
480.00 Hz
Period
2.083 ms
Duty Cycle
66.7%
t(high)
1.386 ms
t(low)
693.00 µs
As an Amazon Associate, we earn from qualifying purchases.
Price as of Jul 24, 2026. Product prices and availability are accurate as of the date indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
Inputs
Result
f = 1.44/((10000+20000)×0.0000001) = 1.44/0.003 = 480Hz. Duty = (10000+10000)/(10000+20000) = 66.7%.
Inputs
Result
T = 1.1 × 10000 × 0.0001 = 1.1 seconds.
In astable mode, the 555 oscillates continuously. Frequency = 1.44 / ((R1 + 2×R2) × C). The output alternates between high and low, with duty cycle determined by R1 and R2 ratio.
| R1 | R2 | C | Frequency | Duty Cycle |
|---|---|---|---|---|
| 10kΩ | 10kΩ | 100nF | 480 Hz | 66.7% |
| 1kΩ | 10kΩ | 100nF | 686 Hz | 52.4% |
| 10kΩ | 10kΩ | 1µF | 48 Hz | 66.7% |
| 100kΩ | 100kΩ | 10nF | 480 Hz | 66.7% |
Monostable produces a single pulse when triggered. Pulse width T = 1.1 × R1 × C. After the pulse, output returns low until triggered again.
Basic astable always exceeds 50%. For 50%, add a diode across R2 so charge and discharge paths are equal, or use R1 much smaller than R2 to approach 50%.
Ceramic caps (100pF–100nF) for high frequencies, film caps (1nF–1µF) for audio, electrolytics (1µF–100µF) for low frequencies. Avoid electrolytics above 10kHz due to ESR.
Electronics, outdoor, and everyday tools
Last Updated: Jul 24, 2026
This calculator is provided for informational and educational purposes only. Results are estimates and should not be considered professional financial, medical, legal, or other advice. Always consult a qualified professional before making important decisions. UseCalcPro is not responsible for any actions taken based on calculator results.