The loss of power in a load that occurs when a network is inserted between the load and the generator supplying the load. Insertion gain occurs when a gain rather than a loss of power results. The loss or gain is usually expressed as the ratio of the power delivered to the load after insertion of the network, to the power delivered to the load before insertion; it is measured in nepers or decibels. The value usually depends not only on the network parameters but also on the load and generator impedances.