I2C上拉电阻计算器
使用此I2C上拉电阻计算器快速获得准确的计算结果。
Average Voltage
2.475 V
Average Voltage vs Peak Voltage (Logic High)
公式
## PWM Average Voltage A PWM signal with fixed amplitude and variable duty cycle produces an average voltage proportional to the duty cycle. ### Formulas **V_avg = V_peak x Duty Cycle** **V_rms = V_peak x sqrt(Duty Cycle)** When filtered through a low-pass filter, the PWM signal approximates a DC voltage equal to V_avg. This principle drives motor controllers, dimmers, and digital-to-analog conversion.
计算示例
3.3 V logic level at 75% duty cycle.
- 01Average voltage: 3.3 x 0.75 = 2.475 V
- 02RMS voltage: 3.3 x sqrt(0.75) = 3.3 x 0.866 = 2.858 V
- 03Power is 75% of continuous DC
常见问题
Is PWM average the same as a true DC voltage?
After filtering, yes. The ripple depends on filter design and PWM frequency. Higher frequency allows smaller filters.
Why use PWM instead of a voltage regulator?
PWM switching is very efficient (95%+) because the transistor is either fully on or off. Linear regulators waste power as heat.
What PWM frequency should I use?
For LEDs: 200+ Hz to avoid flicker. For motors: 1-20 kHz. For audio: 40+ kHz (above hearing range).
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