The document discusses different types of thermometers - a mercury thermometer used to measure human body temperature, a maximum/minimum thermometer invented by James Six for use in greenhouses, and a digital thermometer circuit that uses a 1N4148 diode as the temperature sensor and a digital multimeter to display the measured temperature.

4. • The mercury thermometer is designed to measure
the temperature of the human body; graduated to
cover a range a few degrees on either side of the
normal body temperature The thermometer
consists of mercury contained in a bulb at the
bottom of a graduated sealed glass capillary tube
marked in degrees Celsius or Fahrenheit.

7. Lab thermometer developed during the 16th and 17th centuries, a
thermometer (from the Greek (thermo) meaning "warm" and meter,
"to measure") is a device that measures temperature or
temperature gradient using a variety of different principles.[1] A
thermometer has two important elements: the temperature sensor
(e.g. the bulb on a mercury thermometer) in which some physical
change occurs with temperature, plus some means of converting this
physical change into a numerical value (e.g. the scale on a mercury
thermometer).

10. Six's maximum and minimum thermometer is a popular thermometer
among gardeners for use in greenhouses. Its purpose is to read the
maximum and minimum temperatures reached since the
thermometer was last read. Generally speaking a minimum
temperature occurs during the night and a maximum during the day. It
was invented by James Six towards the end of the eighteenth century,
and consists of a fairly large cylindrical bulb full of alcohol, connected
by a U- shaped stem to a second bulb nearly full of alcohol or oil of
creosote.

13. This digital thermometer circuit diagram uses a common
1N4148 diode as the temperature sensor. The temperature
factor of the diode, -2 mV / 0C is exploited for this application
to create an accurate electronic thermometer. To display the
measured temperature, a digital multimeter is used and so we
can measure temperature values from -9.990C up to +99.90C.