A new circuit-field coupling methodology for a single-phase transformer connected to a half-wave rectifier is presented. The rectifier is composed of switched electronic devices (EDs) which can be modeled through a piecewise-linear approximation technique. The modified nodal analysis (MNA) is used to solve the circuit where the EDs are represented with stamps that are systematically incorporated into the system of differential equations. The transformer is modeled using a 2-D finite-element (FE) approach, leading to a coupled circuit-field system, which is solved using proprietary software. The system is also implemented experimentally using an xPC-Target data acquisition system, showing close correspondence with simulation results. Thus, this paper provides the basis for implementing multi-level power converters connected to transformers.