Voltronics Ceramic Half-Turn SMT Capacitors Voltronics / Knowles Ceramic Half-turn SMT Variable Capacitors are small, inexpensive trimmers available in tape-and-reel format for use with automated assembly equipment. In spite of their small size, they can provide a generous amount of capacitance (up to 100 pF) for high-frequency applications. Used for applications that require adjustable capacitance in a miniature, surface-mountable package at low cost, the Ceramic Half-turn SMT Variable Capacitors provide enough capacitance range to fine-tune filter center frequencies and correct for oscillator drift. The quality factor (Q) of these trimmers is about 1500 at 1 MHz. The temperature coefficient is typically 0 to -750 ppm/°C while capacitance drift ranges from ± 1% to ±5%. These trimmers are generally rated for maximum DC withstanding voltage of about 220 V.