Key Highlights - Material: Semiconductor Materials having high resistivity like Silicon or Germanium and copper - Shape: Round - Also called photoresistor, photocells, photoconductor and photo conducting cell Product Description Light Sensitive Photoresistor LDR - 3mm LDR Stands for Light Dependent Resistor and its Resistivity varies with Incident Electromagnetic Radiations so, its resistivity is a function of Incident Electromagnetic Radiations or light. Other names of LDR are photoresistor, Photoconductor, Photocell, and photo-conducting cell.