What converts light into a charge?

What converts light into a charge?

• A. Diode
• B. Cathode
• C. AC to DC Converter
• D. Photodiode

Answer: (D)

When light shines on a semiconductor device designed to detect it, photons create electron-hole pairs inside the material. In a photodiode, a p-n junction is used and the built-in electric field (often enhanced by reverse bias) quickly separates these charge carriers, generating a current or a measurable charge proportional to the light intensity. This makes the photodiode specifically suited to convert light energy into an electrical signal. A regular diode isn’t designed to respond to light in this way, so it won’t reliably translate light into a charge signal. The other options describe components or processes unrelated to sensing light, so they don’t fit the function described.

When light shines on a semiconductor device designed to detect it, photons create electron-hole pairs inside the material. In a photodiode, a p-n junction is used and the built-in electric field (often enhanced by reverse bias) quickly separates these charge carriers, generating a current or a measurable charge proportional to the light intensity. This makes the photodiode specifically suited to convert light energy into an electrical signal.

A regular diode isn’t designed to respond to light in this way, so it won’t reliably translate light into a charge signal. The other options describe components or processes unrelated to sensing light, so they don’t fit the function described.