This paper presents a comprehensive electromechanical study of an electrostatic kinetic energy harvester (eKEH) biased with a continuous voltage. This simple circuit refers to any capacitive transducer with an in-built voltage source, such as an electret, or DC biased transducer connected directly to a resistive load. It is commonly used for the characterisation of experimental transducers. However there is a void of any unified discussion focusing on the circuits influence on the transducer, due to electromechanical coupling in the transducer. The electromechanical coupling causes numerous nonlinear effects, any of which can result in inconsistent results and disjointed conclusions of experimental devices. This article seeks to present analytic tools which can be employed for systems of this type and discusses some of the results obtained from these techniques. Along with analysis and characterisation of the circuit dynamics, the results are compared with an experimental device and presented in terms of design of the system and conclusions drawn relating to the optimum operation point.