[CobraV8]

Narrow band sensors will give a simple voltage signal output that shows if the AFR is rich or lean. They can't tell you what the exact air/fuel ratio is.

Wide band sensors basicly consist of a narrow band sensor that reads the AFR in a so called pump cell, where the inversed Nernst-effect is used to keep the AFR regulated stoichiomtric. The current that is required to keep AFR at 14.7:1 in this pump cell is proportional to the actual oxygen content in the exhaust gas. With this method the exact AFR can be measured.

Wide band sensors require a controller to operate. All wide band sensors are heated.

Simon