Just five years later the beginning of the silicon revolution spawned the world’s first practical solar cell and its promise for an enduring solar age. Its birth accidentally occurred along with that of the silicon transistor, the principal component of every electronic device in use today. Two scientists, Calvin Fuller and Gerald Pearson of the famous Bell Laboratories, led the pioneering effort that took the silicon transistor from theory to working device. Pearson was described by an admiring colleague as the “experimentalist’s experimentalist.” Fuller, a chemist, learned how to control the introduction of the impurities necessary to transform silicon from a poor to the preeminent conductor of electricity. As part of the research program, Fuller gave Pearson a piece of silicon containing a small concentration of gallium. The introduction of gallium had made the silicon positively charged. When Pearson dipped the rod into a hot lithium bath, according to Fuller’s formula, the portion of the silicon immersed in the lithium became negatively charged. Where the positive and negative silicon met, a permanent electrical field developed. This is the p-n junction, the heart of the transistor and solar cell, where all electronic activity occurs. Silicon prepared this way needs but a certain amount of outside energy for activation, which lamplight provided in one of Pearson’s experiments. The scientist had the specially prepared silicon connected by wires to an ammeter, which, to Pearson’s surprise, recorded a significant electrical current.