Experimental results on the observations of strong potential double layers, characterized by e Delta Phi /kTe>10, in a modified double plasma device are presented. Dependence of the potential jump on various parameters is investigated. Measurements on various characteristics of the potential double layers and their comparison with theoretical and numerical simulation results are presented. It is observed that injection of a large amount of electron current in the target region leads to stronger double layers at larger relative biases. The potential jumps in the device are not limited to the ionization potential of the neutral gas and it is not necessary to resort to specially designed sources on low and high potential sides to obtain strong double layers.