Beginner
20 min
Decibel Fundamentals and Logarithmic Power Ratios
The decibel (dB) is a logarithmic unit expressing the ratio between two power or amplitude values. Using the formula dB = 10·log₁₀(P₂/P₁) for power and 20·log₁₀(V₂/V₁) for voltage, it compresses large dynamic ranges into manageable numbers and converts multiplication/division into addition/subtraction.
Key Concepts
- Compresses large signal ranges into manageable numbers
- Multiplication becomes simple addition (3 dB + 3 dB = 6 dB)
- The 3-6-10 rule: 3 dB = 2×, 6 dB = 4×, 10 dB = 10×
- Common units: dBm (reference to 1 mW), dBW (reference to 1 W)
Visual Reference
Linear Scale
1
10
100
1000
Decibel Scale (dB)
0 dB
10 dB
20 dB
30 dB
See how decibels compress huge ranges into simple numbers
Professional
Approach
20
Minutes
Interactive
Learning