IVa. Measuring Breath Pressure
Two means of measuring pressure (there are others
of course). A diaphram which moves in response
to pressure changes can be connected to an
inductor with moveable coil or core.
(A small speaker, which contains a coil of wire
suspended around a magnet, can be used for this)
A capacitor can be constructed in which one plate
moves in response to changes in pressure.
Measurement of Inductance or Capacitance can be
accomplished by timing transient D.C. response, or
measuring response to a fixed frequency A.C. signal.