Question

Analyze the principle of operation for CCDs in digital imaging. The core function relies on

• A. Conversion of acoustic waves into electrical signals
• B. Direct photon detection without charge transfer
• C. Sequential transfer of charge packets between capacitive bins
• D. Amplification of radio frequency signals

Hint:

In CCDs, light is first converted into charge, then the charge is transferred across the chip and read at one corner, enabling high-quality imaging.

Answer 1

The Correct Option is C

Charge-Coupled Devices (CCDs) are widely used in digital imaging sensors. The core working principle involves the generation and movement of electrical charges (electrons) in response to incident light photons.
Step-by-step working:

• When light photons hit the photosensitive area of a CCD, they generate electron-hole pairs.
• The electrons (charges) are stored in potential wells formed by applied voltages.
• These charges are then transferred sequentially from one capacitor (or potential well) to the next toward a readout register.
• This movement resembles a "bucket-brigade" where charge packets are shifted in a controlled fashion.
• Finally, the charges reach an output node where they are converted into voltage, then digitized.

Why other options are incorrect:

• (A) Refers to acoustic sensors, not CCDs.
• (B) CCDs involve charge transfer; direct photon-to-digital detection without intermediate charge movement is characteristic of some CMOS sensors.
• (D) RF amplification is unrelated to the basic image-capturing function of CCDs.