The newest generation of oxygen sensors are being called "wideband" lambda sensors or "air/fuel ratio sensors" because that's exactly what they do. They provide a precise indication of the exact air/fuel ratio, and over the broadest range of mixtures - all the way from 10:1 to 20:1 air/fuel ratio.
The Bosch LSU 4 wideband oxygen sensor is a 5-wire sensor that reads oxygen in much the same way as a traditional oxygen sensor. but it uses the latest "planar" construction with a special two-part sensing element to measure how much oxygen is in the exhaust.
The Bosch LSU 4 wideband oxygen sensor has a response time of less than 100 milliseconds to changes in the air/fuel mixture, and reaches operating temperature of 700 to 800 degree Centigrade (1,400 degree F) within 20 seconds or less using its internal heater. This is nearly twice the operating temperature of a conventional oxygen sensor.