Speed or Postion Sensor

Formula:

              Frequency =  Probe x volts / div x number of squares and increments

              = (1x10)/3x5 HZ

              = 0.66 HZ

Q. Describe the waveform using arrows and A, B, C and etc. What is happening at different points?

A.The above graph is related to crankshaft angle. Here before arrow "A", there is big gap between the rotor and pickup coil so there is no magnetic field built up yet around pickup coil so not current in the coil. At point "A", the magnetic rotor is that much close to the pickup coil so it starts magnetic field to built up around the coil and so the current in the coil. At "B" the rotor teeth is exactly alined with the pickup coil teeth and at this point the magnetic field around coil is maximum. As the rotor teeth is moving away from pickup coil teeth, the magnetic field start decreasing dramatically and collapsing around the pickup coil and because of this, the current in the coil starts travelling in the opposite direction and went maximum at "C" in reverse direction. As the rotor teeth moves more away from the pickup teeth, the collapsing magnetic field starts diminishing so the current in the coil. When the rotor move much away from the pickup coil teeth, the collapsing field become zero and so the current as shown in the above graph at "D".