Audio Power Amplifier Calculator
Calculate audio amplifier output power, efficiency, THD class estimate, SNR, and input sensitivity for Class A, AB, and D amplifiers.
Formula
P_{out} = \frac{V_{out,peak}^2}{2 R_L},\quad V_{out,peak} = \frac{V_{cc} \times 0.9}{2}
Reference: Cordell, "Designing Audio Power Amplifiers" 2nd ed.
How It Works
Audio power amplifiers convert low-level audio signals into high-power electrical signals capable of driving speakers. The power output calculation depends on several critical parameters including supply voltage, load resistance, and amplifier class. Different amplifier classes have distinct efficiency and distortion characteristics that significantly impact audio performance.
Worked Example
Problem: Calculate maximum output power for a single-supply 12V audio amplifier with an 8Ω speaker load Solution: 1. Vpeak = 0.45 * Vcc = 0.45 * 12V = 5.4V 2. Pout_max = Vpeak²/(2*RL) = (5.4V)²/(2*8Ω) 3. Pout_max = 29.16V²/(16Ω) = 1.82W
Practical Tips
- ✓Choose amplifier class based on required efficiency and sound quality
- ✓Consider thermal management for high-power designs
- ✓Match speaker impedance carefully with amplifier specifications
Common Mistakes
- ✗Ignoring amplifier class efficiency limitations
- ✗Not accounting for peak voltage vs RMS voltage
- ✗Overlooking thermal and load impedance constraints
Frequently Asked Questions
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