The electric current sources that are required for the excitation of the fundamental Gaussian beam and the corresponding full Gaussian light wave are determined. The current sources are situated on the secondary source plane that forms the boundary between the two half-spaces in which the waves are launched. The electromagnetic fields and the complex power generated by the current sources are evaluated. For the fundamental Gaussian beam, the reactive power vanishes, and the normalization is chosen such that the real power is $2\mathrm{W}$ . The various full Gaussian waves are identified by the length parameter $b_t$ that lies in the range $0⩽b_t⩽b$ , where b is the Rayleigh distance. The other parameters are the wavenumber k, the free-space wavelength λ, and the beam waist $w_0$ at the input plane. The dependence of the real power of the full Gaussian light wave on $b_t∕b$ and $w_0∕\lambda$ is examined. For a specified $w_0∕\lambda$ , the reactive power, which can be positive or negative, increases as $b_t∕b$ is increased from 0 to 1 and becomes infinite for $b_t∕b=1$ . For a specified $b_t∕b$ , the reactive power approaches zero as $k{w}_0$ is increased and reaches the limiting value of zero of the paraxial beam.