User talk:Levelsensors-

Optical level sensors 

The mechanical sensor is the simplest and most widely used level sensor. The principle behind magnetic, mechanical, cable and other float level sensor involves the opening or closing of a mechanical switch, either through direct contact with the switch or magnetic operation of a reed. With magnetically actuated float sensors, switching occurs when a permanent magnet sealed inside a float rises or falls to the actuation level. With a mechanically actuated float, switching occurs as a result of the movement of a float against a miniature (micro) switch. The choice of float material also is influenced by temperature-induced changes in specific gravity and viscosity; such changes directly affect buoyancy.

Electro-optic sensors integrate an optical prism tied to solid-state circuitry combining an infrared light emitter and receiver with transistorized switching. They are low cost, compact, level sensors with built-in switching electronics. With no moving parts, these small units are ideal for a variety of point level sensing applications especially where dependability and economy are a must. These sensors are suitable for high, low or intermediate level detection in practically any tank top, large or small. Installation is simple and quick through the tank top, bottom or side.

Electronic sensors almost always have no moving parts, they can be programmed to perform various functions and their size is not a limiting factor in their choice of use. All of these features provide a significant advantage over the float switch device and even the cost is not too dissimilar. The reliability of electronic coolant level sensors is without parallel and they are an automatic choice for many engine manufacturers.