Optogalvanic (OG) signals consist of two, temporally overlapped, separable components (Kumar, D.; McGlynn, S. P. Chem. Phys. Lett., 1991, 176, 536). One of these components is attributable to optically induced ionization rate changes, the other to a photoacoustic effect. These components carry information about many dynamic plasma processes, and the ability to separate the two of them suggests that the OG effect can be used as a weakly perturbative but highly sensitive probe of plasma processes. In this work, we use this sensitivity to accomplish the following : (i) preparation of an OG signal that consists solely of the ionization component; (ii) preparation of an OC signal that consists solely of a photoacoustic component; (iii) demonstration of how to distinguish a true photoacoustic effect from one which leads to electron mobility changes; (iv) demonstration of the role of radiation trapping; (v) demonstration of the effects of the decay branching ratios of optically excited plasma species; (vi) detection of collisional transfer of excitation energy; and (vii) discrimination of the roles played by particular states in the maintenance of the discharge. The effects will be exemplified using low power radiofrequency discharges in neon and iodine.