FLUID LEVEL SENSORS
ISG Fluid Level Sensor
Products
Available in 3 Different Configurations
Each general sensor type can be specified with any one of the 3 dies (sensing active element). The die is chosen upon the desired voltage operating range and type of fluid being sensed. The die changes in resistance with internal heating, such that a hot die has a low resistance. To report that the sensor is in fluid, the internal heat of the die is kept high by losing heat to the fluid surrounding it. When the die is surrounded by air, its heat builds up thus decreasing the die’s resistance.
The dies are:
K12
This is the physically smallest of the 3 dies. It was chosen by the original designer for use in antifreeze/coolant fluids in a 12v nominal system. It does not perform well in more viscous fluids such as oils. Some sensor PNs require K12 dies hand selected for turn on by 9.6v. Others require turn on by 10.8v but their maximum withstanding voltage also is proportionally higher.
LS12
This is the physically largest die. It was chosen by the original designer as a general purpose sensing element as it work with both coolant and oils in 12v nominal systems, but at a slightly higher turn on voltage and thus also a higher maximum withstanding voltage. This is the only one of the 3 dies that we have been successful in re-creating. Turn on voltage requirements range from 10.8v up to 15.6v.
LS24
This is the middle sized one. It is specifically used for all 24v nominal systems in all fluids. Turn on voltage is around 18v and maximum withstanding voltage can be in excess of 28v using hand selected parts.