1. What is Beam Angle?

Beam angle refers to the angle between the two points where the light intensity drops to 50% of the maximum value. It is a crucial parameter in lighting design that determines the spread of light from a source.

2. How Does the Calculator Work?

The calculator uses the beam angle formula:

Where:

• \( \text{Spread} \) — The width of the light beam at the measured distance (feet)
• \( \text{Distance} \) — The distance from the light source to the measurement point (feet)
• \( \arctan \) — The inverse tangent function

Explanation: The formula calculates the full beam angle based on the trigonometric relationship between the spread width and the distance from the light source.

3. Importance of Beam Angle Calculation

Details: Accurate beam angle calculation is essential for proper lighting design, ensuring adequate illumination coverage, avoiding light pollution, and optimizing energy efficiency in various applications including architectural, theatrical, and residential lighting.

4. Using the Calculator

Tips: Enter the spread width in feet and the distance from the light source in feet. Both values must be positive numbers. The calculator will compute the beam angle in degrees.

5. Frequently Asked Questions (FAQ)

Q1: What units should I use for spread and distance?
A: The calculator uses feet for both spread and distance measurements. Ensure consistent units for accurate results.

Q2: Can I use meters instead of feet?
A: Yes, but you must use the same unit for both spread and distance (either both in feet or both in meters).

Q3: What is a typical beam angle range?
A: Beam angles typically range from narrow spotlights (10-30 degrees) to wide floodlights (90-120 degrees) to very wide wash lights (120+ degrees).

Q4: How does beam angle affect lighting design?
A: Narrower beams provide more focused, intense light while wider beams offer broader, more diffuse illumination. The choice depends on the specific lighting application and desired effect.

Q5: Are there different types of beam angle measurements?
A: Yes, besides the 50% intensity points used here, some manufacturers may specify beam angles at 10% intensity points (field angle) which gives a wider measurement.