What is one reason phototransistor technology is replacing photoresistor technology?

• A. Silicon is more resistant to high temperature
• B. Phototransistors are cheaper
• C. Phototransistors require more power
• D. Photoresistors are faster

Answer: (A)

Photodetection performance in varying temperatures is a key factor in choosing sensing components. Silicon-based phototransistors handle higher temperatures with less drift and more stable sensitivity than photoresistors, which are typically made from cadmium sulfide and suffer from strong temperature dependence and slower, more variable responses. This greater temperature resilience means phototransistors maintain reliable performance in hot or thermally changing environments, making them a preferred choice as a replacement for photoresistors in many applications. The other statements aren’t generally true: phototransistors aren’t universally cheaper, they’re not inherently more power-hungry, and photoresistors are not faster (they’re actually slower).