how does an LDR work in dark?...... answer fast!!
Dear Student,
Photo conductivity is the principle behind the working of a LDR. When light falls on the device, the electrons in the valence band of the semiconductor material are excited to the conduction band. These photons have energy greater than the band gap of the semiconductor material so they jump from the valence band to the conduction band. Hence more and more electrons are excited to the conduction band which results in large number of charge carrier thus current starts flowing through the device.
Regards
Photo conductivity is the principle behind the working of a LDR. When light falls on the device, the electrons in the valence band of the semiconductor material are excited to the conduction band. These photons have energy greater than the band gap of the semiconductor material so they jump from the valence band to the conduction band. Hence more and more electrons are excited to the conduction band which results in large number of charge carrier thus current starts flowing through the device.
Regards