Attenuation Factor (K)
K = 10^(dB / 20)
Quick answer
This calculator solves K = 10^(dB / 20) (voltage ratio) for Voltage Ratio K. With Attenuation 20 dB, the result is 10. It solves in 2 directions, so you can enter the values you have and get the one you need.
Calculator
Formula
Description
The attenuation factor K is the linear voltage ratio corresponding to a decibel attenuation, and it is the quantity that all resistive-pad design equations use. A 6 dB pad has K ≈ 2 (halves the voltage), and a 20 dB pad has K = 10. Converting the desired dB loss to K is the first step in designing any T, Pi, L, or bridged-T attenuator.
Variables
- K — Voltage attenuation ratio (input/output)
- dB — Attenuation in decibels
Practical Notes
For a power ratio use K = 10^(dB/10). K is always ≥ 1 for an attenuator; the pad resistor formulas below all take this K.
Symbols and units
| Symbol | Meaning | Default unit | Accepted units |
|---|---|---|---|
| K | Voltage Ratio K | — | — |
| dB | Attenuation | dB | dB |
Step by step
- 1. What you know: Attenuation 20 dB
- 2. The relation: K = 10^(dB / 20) (voltage ratio)
- 3. Substitute: dB = 20 dB
- 4. Result: Voltage Ratio K = 10
Worked examples
Minimum range
Given: Attenuation 0.3 dB
Result: Voltage Ratio K = 1.035
Low range
Given: Attenuation 3 dB
Result: Voltage Ratio K = 1.413
Typical
Given: Attenuation 20 dB
Result: Voltage Ratio K = 10
High range
Given: Attenuation 60 dB
Result: Voltage Ratio K = 1000
Maximum range
Given: Attenuation 0.6 dB
Result: Voltage Ratio K = 1.072
Solving for each variable
Solve for Voltage Ratio K
Attenuation 0.3 dB → 1.035
Solve for Attenuation
Voltage Ratio K 0.025 → -32.04 dB
How Voltage Ratio K changes with Attenuation
| Attenuation (input) | Voltage Ratio K (result) |
|---|---|
| 2 dB | 1.259 |
| 5 dB | 1.778 |
| 10 dB | 3.162 |
| 15 dB | 5.623 |
| 20 dB | 10 |
| 30 dB | 31.62 |
| 40 dB | 100 |
| 80 dB | 10000 |
| 140 dB | 1 × 10⁷ |
| 200 dB | 1 × 10¹⁰ |
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<p><a href="https://vbatpower.com/formulas/attenuation-factor-k/">Attenuation Factor (K)</a> Calculator by vbatpower.com</p>Frequently asked questions
How do you calculate Attenuation Factor (K)?
Use K = 10^(dB / 20) (voltage ratio). With Attenuation 20 dB, Voltage Ratio K works out to 10.
What is the formula for Attenuation Factor (K)?
The formula is K = 10^(dB / 20) (voltage ratio). The attenuation factor K is the linear voltage ratio corresponding to a decibel attenuation, and it is the quantity that all resistive-pad design equations use.
How do you find Attenuation when you know the other values?
Rearrange for Attenuation: with Voltage Ratio K 0.025, Attenuation is -32.04 dB.
Related Concepts
All Attenuators & Pads formulas →Need more features?
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