where W c is the collector's thermionic work function, Δ V ce is the applied collector–emitter voltage, and Δ V S is the Seebeck voltage in the hot emitter (the influence of Δ V S is often omitted, as it is a small contribution of order 10 mV). The resulting current density J c through the collector (per unit of collector area) is again given by Richardson's Law, except now