Reed sensors in Accurate fuel level sensing
Automobile fuel gauges are used to display the volume of fuel in the tank. These gauges require a potentiomteric feedback from within the fuel tank which is triggered by a magnet in a foamed float. For the PCB to generate such an output, reed Sensors need to be combined with resistors. More information about the design of such PCB circuits can be seen here. The space available in larger automobiles such as trucks is more, but for cars, the fuel tank is usually long and wide with a very short height. This mean that the design of the PCB would need to be very compact, with reed switches mounted very close to each other to ensure that at any given time, at least one reed switch is always in an actuated state. Specially designed reed sensors with a high differential need to be used and are combined with integrated resistors. For larger fuel tanks however, standard reed switches with a regular 45% differential can be used. These PCBs give out a potentiometric feed back across two outputs as a foamed magnetic float moves along its height. The PCB tracks can be designed in such a way that a full tank gives high resistance and an empty tank gives low resistance, or vice versa. Being hermetically sealed devices, reed sensors are the best devices to use in explosive environments such as fuel tanks. Suitable products:
Applications are classified as Position Sensing, Pulse Counting, Electromagnetic or Relay, Temperature Sensing or Magnet Biasing types. This application is classified as follows and the link gives more information on best practices to help select the most suitable AT band and matching magnet.
The Reed Switches and Sensors used in such applications need to be robust, durable and efficient in meeting a high life expectancy. Our engineers work hard in life testing our products under various conditions, and our intention is to ensure end product durability and life. Although we wouldn’t want to restrict any of our products for use in only certain applications, the recommended products for use in this application are listed below.
R3 Miniature SMD Reed Sensor
|Omni polar, normally open (NO), 16.25 mm SMD and low-profile SMD pitch. 10 W...Continue reading|
MM-1018 Micro Miniature Reed Switch
|This is durable and reliable, Form A type 10.0 mm Micro Miniature reed switch...Continue reading|
MS-105 Miniature PCB Mountable Reed Sensor
|This micro miniature PCB mountable reed sensor is designed for switching 10W. The sensors...Continue reading|