Candela To Watts Calculator

Candela to Watts Formula:

\[ W = \frac{cd \times (2\pi (1 - \cos(\alpha/2)))}{Eff} \]

Power (W):

Unit Converter ▲

Unit Converter ▼

From:	To:

1. What is Candela to Watts Conversion?

The candela to watts conversion calculates the electrical power required to produce a specific luminous intensity, taking into account the beam angle and the efficacy of the light source. This is particularly useful in lighting design and energy efficiency calculations.

2. How Does the Calculator Work?

The calculator uses the formula:

\[ W = \frac{cd \times (2\pi (1 - \cos(\alpha/2)))}{Eff} \]

Where:

\( W \) — Power in watts
\( cd \) — Luminous intensity in candela
\( \alpha \) — Beam angle in degrees
\( Eff \) — Efficacy in lumens per watt (lm/W)

Explanation: The formula accounts for the angular distribution of light (beam angle) and the efficiency of converting electrical power to light (efficacy).

3. Importance of Light Power Calculation

Details: Accurate power calculation is essential for designing energy-efficient lighting systems, determining power requirements, and optimizing light source selection for specific applications.

4. Using the Calculator

Tips: Enter candela value, beam angle in degrees, and efficacy in lumens per watt. All values must be positive numbers for accurate calculation.

5. Frequently Asked Questions (FAQ)

Q1: What is the difference between candela and watts?
A: Candela measures luminous intensity (perceived brightness), while watts measure electrical power consumption. The conversion depends on beam angle and efficacy.

Q2: How does beam angle affect power calculation?
A: Wider beam angles distribute light over a larger area, requiring more power to maintain the same luminous intensity compared to narrow beam angles.

Q3: What are typical efficacy values for different light sources?
A: Incandescent: 10-17 lm/W, LED: 80-150+ lm/W, Fluorescent: 50-100 lm/W. Efficacy continues to improve with technology advancements.

Q4: Can this calculator be used for all light sources?
A: Yes, but ensure you use the appropriate efficacy value for the specific light source technology being evaluated.

Q5: Why is the cosine function used in the formula?
A: The cosine function accounts for the angular distribution of light intensity, which follows a cosine pattern in many lighting applications.