PRESSURE DETECTION CIRCUITRY
Another type of inductance transducer, illustrated in Figure 8, utilizes two coils wound on a
single tube and is commonly referred to as a Differential Transformer.
Figure 8 Differential Transformer
The primary coil is wound around the center of the tube. The secondary coil is divided with one
half wound around each end of the tube. Each end is wound in the opposite direction, which
causes the voltages induced to oppose one another. A core, positioned by a pressure element,
is movable within the tube. When the core is in the lower position, the lower half of the
secondary coil provides the output. When the core is in the upper position, the upper half of the
secondary coil provides the output. The magnitude and direction of the output depends on the
amount the core is displaced from its center position. When the core is in the mid-position, there
is no secondary output.