LIFETIME TESTER : The picture shows Bhumika Chhabra using the Sinton Lifetime Tester for characterizing silicon solar cells. It measures the lifetime of silicon substrates when the flash light falls on it. The sample gets inductively coupled by the coil to an rf bridge circuit when placed on the lifetime tester stage. This causes change in wafer’s permeability and thus its conductance. The illumination intensity measured from the reference solar cell gives the number of photons incident on the sample. Its features include measurement of resistivity, lifetime, trap density, emitter saturation current density and implied open circuit voltage.