Photoconductivity Experiment


Objectives

To study the photoconductivity of CdS Photoresistor, in the following conditions:

  • Applied voltage vs photocurrent (IPH) at constant irradiance (Φ).
  • Photocurrent (IPH) vs irradiance (Φ) at a constant applied voltage (V).

 

Principle

The phenomenon of photoconductivity occurs when an incident light shown upon a semiconductor causes an increase in its electrical conductivity. This is because of the excitation of electrons across the energy gap into the conduction band, which leads to an increase in the number of free carriers in the conduction band, hence, an increase in the conductivity of the semiconductor. Here, we can study the characteristics of the CdS photoresistor under different conditions of light intensity and applied voltage.

KEY FEATURES

  • Precise Optical Alignment: The optical alignment of the components is attained by the optical bench, the set-up time is faster and experimentation is easy.
  • Fine and Easy Light Intensity Adjustment: Light intensity adjustment is done via the use of two polarizers. This helps in easier and fine light intensity adjustments.
  • Simple and Easy Connections: The color-coded terminals on the various components aid in the ease of connections thus reducing the setup time.

WHAT YOU NEED

  • OB2 Optical Bench Set 0.4m 1
  • HA001 Light Source Holder 1
  • HA004 Polarizer Holder 1
  • HA006 Analyzer Holder 1
  • HA020 LDR Module Holder 1
  • PH61022D/20 Power Supply, 0-15V, 200mA 1
  • PH61022D/2 Power Supply for Light Source 1
  • PCE1-C: Complete Equipment Set With Instruction Manual
PCE1-C