The analysis of transients in nuclear power plants is a complex problem normally requiring use of simulation tools. Although analog computers have been used for dynamic simulation, the most common approach involves use of a digital computer. An alternative method to attack the same problem, known as parity simulation, is described. Parity simulation, which originated in the study of electronic network transients, exploits the concept of electrical analogs of a physical system. Electrical analogs of the components of a system are constructed and interconnected in a highly user-oriented facility known as a parity simulator. The application of parity simulation to transient thermal-hydraulic single-phase flow is described. The development of a single-phase incompressible flow element is described. The governing mass, momentum, and energy equations along with other conditions are applied to a pipe section. The resulting model is then used to construct a circuit analog. The proposed circuit analog requires nonstandard components, the design and implementation of which is discussed. Subsequently, a formulation for single-phase compressible flow is given. Results obtained for different cases are presented. Comparison with reference numerical solutions shows general agreement.