免费555定时器无稳态计算器
计算555定时器无稳态多谐振荡器的频率和占空比。
kΩ
kΩ
µF
频率
480.0 Hz
周期2,083.333 ms
占空比66.7 %
Frequency vs R1
公式
## 555 Timer Astable Mode ### Formulas **f = 1.44 / ((R1 + 2R2) x C)** **Duty Cycle = (R1 + R2) / (R1 + 2R2) x 100%** Duty cycle is always above 50% in standard configuration. Use a diode across R2 for below 50%.
计算示例
R1 = 10k, R2 = 10k, C = 0.1 uF.
- 01f = 1.44 / ((10000 + 20000) x 0.0000001) = 1.44 / 0.003 = 480 Hz
- 02Duty cycle = (10 + 10) / (10 + 20) x 100 = 66.7%
常见问题
Can duty cycle be below 50%?
Not in standard configuration. Place a diode across R2 so it is bypassed during discharge to achieve sub-50% duty cycle.
How accurate is a 555 timer?
Typically within a few percent. Temperature and component tolerance cause drift.
What is the maximum frequency?
Standard 555 works reliably up to about 500 kHz. CMOS versions can reach several MHz.
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