2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/229584The expression for the electromagnetic field of a charge moving along an arbitrary trajectory is obtained in a direct, elegant, and Lorentz invariant manner without resorting to more complicated procedures such as differentiation of the Lienard-Wiechert potentials. The derivation uses arguments based on Lorentz invariance and a physically transparent expression originally due to J.J.Thomson for the field of a charge that experiences an impulsive acceleration.The following article has been accepted by the American Journal of Physics. After it is published, it will be found at http://scitation.aip.org/ajp; 12 pages, 1 figureClassical PhysicsGeneral Relativity and Quantum Cosmologytext