Niobium capacitor
The development of solid electrolyte tantalum capacitors began in the early 1950s as a miniaturized, more reliable low-voltage support capacitor to complement the newly invented transistor. The solution found by R. L. Taylor and H. E. Haring of the Bell Labs was based on experience with ceramics. They ground down tantalum to a powder, pressed this powder into a cylindrical form and then sintered the powder particles into a pellet (“slug”) at high temperatures, between 1500 and 2000 °C, under vacuum conditions. These first sintered tantalum capacitors used a non-solid electrolyte not consistent with the concept of solid state electronics. 1952 a targeted search in the Bell Labs for a solid electrolyte by D. A. McLean and F. S. Power led to the invention of manganese dioxide as a solid electrolyte for a sintered tantalum capacitor.
William Dubilier
William Dubilier (July 25, 1888 – July 25, 1969) was an American inventor in the field of radio and electronics. He demonstrated radio communication at Seattle's Alaska-Yukon-Pacific Exposition on June 21, 1909; ten years before the first commercial station operated. A graduate of Cooper Union, he was the first to use sheets of naturally occurring mica as the dielectric in a capacitor. Mica capacitors were widely used in early radio oscillator and tuning circuits because the temperature coefficient of expansion of mica was low, resulting in very stable capacitance – mica capacitors are still used where exceptional temperature stability is needed.