Berliner Gramophone formulations remained the standard disc record material until the first vinyl records – initially made only for radio use and other special applications – were introduced in the 1930s. Beginning in 1896, Berliner's gramophones were made by Philadelphia-based machinist Eldridge Johnson, who added a spring motor to drive the previously hand-rotated turntable. Berliner also opened an office in New York City, staffed by Frank Seaman and O. D. LaDow and organized as the National Gramophone Company. Master recordings were made onto zinc plates, which were then electroplated and a negative-image "mother" made from them to stamp discs. A major reversal
Polymer capacitor aluminum oxide and tantalum pentoxide have little impact on the specific capacity due to different safety margins in oxide layers. Polymer Ta-e-caps use an oxide layer thickness that corresponds to approximately four times the rated voltage, while the polymer Al-e-caps have about twice the rated voltage. Cylindrical polymer aluminum capacitors based on the technique of wound aluminum electrolytic capacitors with liquid electrolytes. They are available only with aluminum as anode material. They are intended for larger capacitance values compared to rectangular polymer capacitors. Due to their design, they may vary in height on a given surface mounting area so that