E1C12 09/14/2010
13:54:10 Page 521
where
B ¼ magnetic field strength
D c ¼ coil diameter
emf ¼ induced electromotive force
N ¼ number of turns in coil
dy=dt ¼ velocity of coil linear motion
l ¼ coil length
A moving coil transducer is appropriate for vibration applications in which the velocities of
small amplitude motions are measured. The output voltage is proportional to the coil velocity, and
the output polarity indicates the velocity direction. Static sensitivities on the order of 2 V-s/m are
Figure 12.14 Result of numerical differentiation of the noisy signal from Figure 12.12.
y
S
N
S
Figure 12.15 Moving coil transducer.
12.2 Sensors 521
13:54:10 Page 521
where
B ¼ magnetic field strength
D c ¼ coil diameter
emf ¼ induced electromotive force
N ¼ number of turns in coil
dy=dt ¼ velocity of coil linear motion
l ¼ coil length
A moving coil transducer is appropriate for vibration applications in which the velocities of
small amplitude motions are measured. The output voltage is proportional to the coil velocity, and
the output polarity indicates the velocity direction. Static sensitivities on the order of 2 V-s/m are
Figure 12.14 Result of numerical differentiation of the noisy signal from Figure 12.12.
y
S
N
S
Figure 12.15 Moving coil transducer.
12.2 Sensors 521