| abstract |
A planar polarographic probe for determining the λ value of gas mixtures, in particular of exhaust gases of internal combustion engines, having at least the following units: a pumping cell (A), a diffusion unit (B) with a diffusion resistance preceding a pumping electrode of the pumping cell (A) and, if necessary, a heating unit (C) is proposed in which the diffusion resistance of the diffusion unit (B) is formed by a preshaped body which becomes porous on sintering and which is inserted into the unsintered probe. n Such a polarographic probe enables a sensor to be constructed in a simple manner which is particularly suitable for production, with increased reproducibility of the diffusion resistance. |