Magnetic penetration depth, ${\ensuremath{\lambda}}_{m}$, was measured as a function of temperature and magnetic field in single crystals low carrier density superconductor YPtBi by using tunnel-diode oscillator technique. Measurements zero DC yield London ${\ensuremath{\lambda}}_{L}(T)$, but the applied signal includes Campbell ${\ensuremath{\lambda}}_{C}(T)$, which is characteristic length at...