A calculation is made of the absorption current, dielectric constant, and dielectric loss expected from electron tunnelling into a single trapping level in a dielectric. Plots are given of current versus time, and of dielectric constant, dielectric loss, and loss tangent against frequency. This model reproduces the approximatet−ndependence of absorption current (t=time, n≃1) and nearly constant tan&dgr; observed experimentally in many insulators. Numerical comparison with experiment shows that this model may apply to the case of high polymers, but is unable to account for the higher absorption currents occurring in oxides and similar inorganic dielectrics.