Theory Of Operation; Sensor - Teledyne TED 200-T Instruction Manual

1 Introduction
The monitor may be used for verifying oxygen concentrations in gas mixtures
used in:
• Anesthesia
• Respiratory Therapy
• Neonatal Care.
1.2

Theory of Operation

The TED 200-T can be divided into two major functional groups:
• the T-7 Sensor and
• Signal Processing.
The analyzer uses Teledyne Electronics Technologies Class T-7 oxygen sensor.
The current output from the sensor is fed into the electronic signal processor, where it
is used to calculate the oxygen gas concentration and display it on the LCD screen.
The data from the sensor is compared to values set by the user, and sets off the alarms
if it exceeds those values.

1.2.1 Sensor

The T-7 oxygen sensor is a galvanic cell that is made up of a cathode and anode
immersed in electrolyte and packaged in a small plastic container. Oxygen entering
the sensor stimulates a proportional amount of electrical current between the anode,
cathode and electrolyte. This current is sent to the microprocessor, which measures
and displays it as a percentage on the LCD screen, and then compares it to the alarm
standards set by the user. If it exceeds alarm limits, the alarms are triggered.
CAUTION: The electrolyte used in the T-7 sensor is caustic. Do not try
to open the sensor assembly. Check the sensor regularly
for leaks. If the sensor is leaking, discard of it in a safe
manner. Do not try to repair it. Consult the Material Safety
Data Sheet in the Appendix for handling guidelines.
Attached to the T-7 sensor is a removable plastic diverter. This diverter is used to
facilitate the transport of gas mixtures through the sensor. The diverter, packaged
separately when shipped, is necessary when the tee adapter is used to sample gas
flowing through a tube.
The diverter is not necessary and should not be used when the sensor is placed
directly in a chamber, or when the sensor is used in confined volume monitoring, such
as incubators and inhalation tents.
1-2 Teledyne Analytical Instruments