Semiconductor wafer. Semiconductor wafer (lower frame) and fiber optic cables (at upper right). Wafers are divided up into blocks to make the integrated circuits ("chips") used in electronic devices. Integrated circuits are made by impregnating the wafer with impurities to create transistors. Tens of thousands of transistors can be fitted on a single chip and connected by conducting pathways. Fiber optic cables are made from a flexible glass within a protective coating. They internally reflect light pulses almost without attenuation. The light can be used to carry the large volumes of data produced or required by electronic devices.