Magneto Resistive Element (MRE) in the top of the
magnet detects the rotation of the magnet and
generates a 4-pulse electric signal for each rotation o
the speedometer driven gear.
the direction of the magnetic field is vertical to the
Magneto Resistive Element (MRE), the resistance value
is minimum.
into a 1rotation, 4-pulse signal, the transistor turns it ON-
OFF when it is output to the transistor base to produce a
4-pulse electric signal per one rotation of the
speedometer driven gear.
ELECTRICAL - Meters and Gauges 7-15
EHICLE SPEED SENSOR
STRUCTURE
The rotating shaft of the vehicle speed sensor is
mounted directly on the transmission speedometer
driven gear. The rotation of the driven gear is transmitted
to a magnet via the rotating shaft. The IC built into the
Characteristics
The magneto resistive element (M R E) has the
characteristic that its resistance value varies according
to the direction of the magnetic field. When the direction
of the magnetic field is parallel to the Magneto Resistive
Element (MRE), the resistance value is maximum; when
Operation
Since the resistance value of the MRE varies with the
variations in the magnetic field when the magnet rotates,
the output voltage also varies. The shape of the wave o
this output voltage is shaped by the comparator and
then, after it is divided by the frequency divider circuit
MAGNETO RESISTIVE ELEMENT (MRE)
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