Electron paramagnetic resonance of ensembles of phosphorus donors in silicon has been detected electrically with externally applied magnetic fields lower than 200 G. Because the spin Hamiltonian was dominated by the contact hyperfine term rather than by the Zeeman terms at such low magnetic fields, superposition states alpha vertical bar up down arrow > + beta vertical bar down arrow up arrow > and -Chi vertical bar up down arrow > + alpha vertical bar down arrow up arrow > were formed between phosphorus electron and nuclear spins, and electron paramagnetic resonance transitions between these superposition states and vertical bar up arrow up arrow > and vertical bar down arrow down arrow > states are observed clearly. A continuous change of alpha and beta with the magnetic field was observed with a behavior fully consistent with theory of phosphorus donors in silicon.