Modern Dictionary of Electronics, 7th Edition

Q

Q 1. Also called quality factor or Q factor. A measure of the relationship between stored energy and rate of dissipation in certain electric elements, structures, or materials. In an inductor or capacitor, the ratio of its reactance to its effective series resistance at a given frequency. 2. A measure of the sharpness of resonance or frequency selectivity of a mechanical or electrical system. 3. Figure of merit for energy-storing device, tuned circuit, or resonant system. 4. Half-width of power spectrum of bandpass filter response in hertz divided by the center frequency in hertz. 5. The figure of merit of a resonator, defined as twice the average energy stored in the resonator divided by the energy dissipated per cycle. The higher the ...