Diffusion is linearly dependent on the partial pressure gradient, but is also temperature dependent, and the current rises about two to three percent per kelvin rise in temperature. A negative temperature coefficient resistor is used to compensate, and for this to be effective it must be at the same temperature as the cell. Oxygen cells which may be exposed to relatively large or rapid temperature changes, like rebreathers, generally use thermally conductive paste between the temperature compensating circuit and the cell to speed up the balancing of temperature.