  The quasinormal spectrum of a charged scalar field around a non-extremal
Reissner-Nordstr\"om black hole, specially in the limit of large
electromagnetic interaction, has been comprehensively studied only very
recently. In this work, we extend the analysis to Dirac fields using the
continued fraction method and compare the results with the scalar case. In
particular, we study the behaviour of the fundamental quasinormal mode as a
function of the black hole's charge and of the electromagnetic interaction
parameter. We derive an analytical formula for the quasinormal frequencies in
the limit of large electromagnetic interaction. As the extremal limit of black
hole charge is approached, we show that, unlike the case of neutral fields, the
imaginary part of the quasinormal frequencies approach zero for charged fields.
