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Voltage from dB Formula:
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The decibel (dB) to voltage conversion calculates the actual voltage level from a dB value relative to a reference voltage. This is commonly used in audio engineering, telecommunications, and electronics to express voltage ratios logarithmically.
The calculator uses the formula:
Where:
Explanation: The formula converts a dB value (which represents a ratio relative to a reference) back to an absolute voltage value. The division by 20 in the exponent is used because power ratios use 10, while voltage ratios use 20 (since power is proportional to voltage squared).
Details: This conversion is essential for interpreting dB measurements in practical applications, designing electronic circuits, setting audio levels, and calibrating measurement equipment.
Tips: Enter the reference voltage in volts and the dB value. The reference voltage should be a positive value. Both values can be positive or negative, but the reference voltage must be greater than zero.
Q1: Why is there a division by 20 in the exponent?
A: Because dB is defined for power ratios as 10·log₁₀(P/P_ref), and since power is proportional to voltage squared (P ∝ V²), the formula becomes 20·log₁₀(V/V_ref) for voltage ratios.
Q2: What is a typical reference voltage?
A: Common reference voltages include 1V (for dBV), 0.775V (for dBu), or other standard values depending on the specific application and measurement standard.
Q3: Can dB values be negative?
A: Yes, negative dB values indicate that the voltage is less than the reference voltage. For example, -6 dB means the voltage is half the reference voltage.
Q4: What does 0 dB represent?
A: 0 dB means the voltage is exactly equal to the reference voltage (V = V_ref).
Q5: How accurate is this conversion?
A: The conversion is mathematically exact. The accuracy in practical applications depends on the precision of your measurements and the stability of your reference voltage.