1. What is Candlepower?

Candlepower is a unit of measurement for luminous intensity. It describes how much light is produced in a specific direction, which is particularly important for focused light sources like spotlights and flashlights.

2. How Does the Calculator Work?

The calculator uses the candlepower formula:

Where:

• \( Lumens \) — Total luminous flux (lm)
• \( \theta \) — Beam angle (degrees)
• \( \pi \) — Mathematical constant pi (≈3.1416)
• \( \cos \) — Cosine trigonometric function

Explanation: This formula converts total light output (lumens) to directional intensity (candlepower) based on the beam spread angle.

3. Importance of Candlepower Calculation

Details: Candlepower is crucial for applications where directional lighting is important, such as automotive headlights, flashlights, spotlights, and theatrical lighting. It helps determine how focused or spread out a light beam will be.

4. Using the Calculator

Tips: Enter total lumens and beam angle in degrees. Both values must be positive numbers. The beam angle represents the full width of the light beam where intensity drops to 50% of maximum.

5. Frequently Asked Questions (FAQ)

Q1: What's the difference between lumens and candlepower?
A: Lumens measure total light output in all directions, while candlepower measures light intensity in a specific direction.

Q2: Why does beam angle affect candlepower?
A: A narrower beam concentrates the same total light into a smaller area, resulting in higher intensity (candlepower) in that direction.

Q3: What are typical candlepower values?
A: Values vary widely: flashlight (10-1,000 cd), car headlight (20,000-50,000 cd), lighthouse (1,000,000+ cd).

Q4: Is candlepower the same as candela?
A: Yes, candlepower is essentially the same measurement as candela (cd), with 1 candlepower = 0.981 candela historically, but now they're used interchangeably.

Q5: When is this calculation most useful?
A: This is particularly useful for comparing the throw distance of different flashlights or designing lighting systems where beam control is important.