Abstract: An exhaust emissions analyzer for an automotive internal combustion engine has sensors for detecting constituents of the exhaust emissions, including a nitric oxide cell which receives the emissions and outputs an electrical signal indicative of nitric oxide in the emissions. An R-C circuit is interposed between the output of the nitric oxide cell and processing circuitry for enhancing the response time of the nitric oxide cell, reducing the rise and fall times of the cell output of signal. A temperature-responsive switching circuit disconnects the R-C enhancement circuit above a predetermined ambient temperature.