2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/87477We comment on the paper by M. W. Mitchell and R. Y. Chiao, ``Causality and negative group delay in a simple bandpass amplifier", Am. J. Phys. 66 (1), 14-19 (1998).LaTeX file, 2pp. Submitted to Am. J. PhysGeneral Physicstext