Question

Name the device which converts the change in intensity of illumination to change in electric current flowing through it. Plot I-V characteristics of this device for different intensities. State any two applications of this device.

Answer 1

Photodiodes are used to detect optical signals of different intensities by changing current flowing through them.

I-V Characteristics of a photodiode

Applications of photodiodes:

1. In detection of optical signals. 

2. In demodulation of optical signals. 

3. In light operated switches. 

4. In speed reading of computer punched cards. 

5. In electronic counters