The document discusses pressure monitoring systems and instrumentation amplifiers. It describes how instrumentation amplifiers can be used in biomedical applications like electrocardiography machines to monitor changes in electric fields. The document also provides examples of how instrumentation amplifiers can be used to build simple temperature controllers, temperature indicators, and light intensity meters by using transducers like thermistors or light dependent resistors in a resistive bridge circuit.

1. Pressure monitoring system

2. • A pressure monitoring system especially
suitable for use with extra-corporeal
circulation
systems such as dialyzers, blood cell
separators, oxygenators and the like, in which
the
internal system pressure must be monitored
at one or more locations in the blood circuit,
...

3. Applications
• Weigh scales
• ECG and medical instrumentation
• Transducer interface
• Data Acquisition systems
• Industrial process controls
• Battery powered and portable equipment

4. Instrumentation amplifier
. An instrumentation amplifier is a type of
differential amplifier that has been outfitted
with input buffer amplifiers, which eliminate
the need for input impedance matching and
thus make the amplifier particularly suitable
for use in measurement and test equipment.

5. Practical Uses of
Instrumentation Amplifiers
• Measurement Applications
One of the applications these circuits are used for
is taking measurements from sensors and
transducers. An instrumentation amp can amplifies
floating signals because it only amplifies the
difference between the two input terminal.

6. Biomedical Applications
• An easily recognizable medical application for amplifiers like
these is in electrocardiography machines, or ECGs; which
monitor the changes in the heart’s dipole electric field. Below
is the implementation of Analog Device’s AD82X series of
instrumentation amplifier in an ECG, from their application
manual.

7. Temperature Controller
simple temperature controller system can be
constructed using a thermistor as the
transducer device, in the resistive bridge, as
shown in the figure above. The resistive bridge
is kept balanced for some reference
temperature. For any change in this reference
temperature, the instrumentation amplifier
will produce an output voltage, which drives
the Relay which in turn turns ON/OFF the
heating unit, thereby controlling the
temperature.

9. • The circuit shown for temperature controller can
also be used as a temperature indicator. The
resistive bridge is kept balanced for a particular
reference temperature when Vo = 0V. The
temperature indicating meter is calibrated to
reference temperature, corresponding to this
reference condition. As temperature changes, the
amplifier output also changes. The gain of the
amplifier can be appropriately set to indicate the
desired range of temperature
Temperature Indicator:

10. Light Intensity Meter:
• The same circuit can be used to detect
variations in the intensity of light, by replacing
the thermistor by a Light Dependent Resistor
(LDR). The bridge is set to a balanced
condition in darkness. When light falls on the
LDR, its resistance changes and unbalances
the bridge. This causes the amplifier to
produce a finite output, which in turn drives
the meter.

11. Reference
• http://www.electronicshub.org/instrumentati
on-amplifier-basics-applications/
• http://www.allaboutcircuits.com/technical-
articles/practical-uses-of-instrumentation-
amplifiers/