I have always wondered if cheap and expensive digital medical thermometers differ in accuracy and measurement speed. Finally I checked it out.
Three models of contact medical thermometers were purchased for the experiment: Omron Eco Temp Smart MC-341-RU (660 rubles), Omron Eco Temp Basic MC-246-RU (434 rubles), AnD DT-501 (288 rubles) and taken a cheap Chinese unnamed thermometer, which can be found on sale under many different brands.
The packaging of the AnD thermometer reads "Average measurement time - 60 seconds", the packaging of the Omron Basic There is nothing about the time, the Omron Smart packaging says "Beep interval from 10 seconds. ".
The instructions say the following:
Have And: "The temperature measurement time is individual for each person, so the sound signal on the end of the measurement will sound when the rate of temperature rise is less than 0.1 ° C in 32 seconds. To obtain more accurate readings, the thermometer should be left in the armpit for about 2-3 minutes after the beep. "
With Omron Basic: "Measurement in the armpit: approx. 2 minutes * ".
With Omron Smart: "Measurement in the armpit: approx. 25 seconds * ".
And under the asterisk on both Omrons it is written: "The sound signal is given when the change in the measured temperature becomes sufficiently insignificant, thus reporting an approximate measurement result, and allows an assessment of the general condition organism. It may take a longer time to get the final result, as indicated in the chapter "Characteristics".
In the Characteristics of both thermometers it is stated: "Measurement time in the armpit is not more than 10 minutes."
This is how 10 seconds turns into 10 minutes. :)
I compared the results of digital thermometers with those of a mercury thermometer.
First, I ran the test in warm water.
Thermometers were fixed over a container of warm water. The water was stirred before measurement.
Digital thermometers readings are close to mercury readings, but Omron Basic at low temperatures was wrong by 0.2 ° C.
Then I conducted tests on the "experimental" myself.
The temperature was measured under the arm. The temperature values were recorded 1, 2, 3, 5, 7, 10 minutes after the start of the measurement. In addition, the time from the start of the measurement to the sound signal and the temperature reading at that moment were recorded.
For control, I repeated this test one more time, although it took another hour.
I recently talked about how to improve the measurement accuracy with such a thermometer (https://ammo1.livejournal.com/1227382.html ), so I did another test: the turned off thermometer was placed in the armpit and turned on after 5 minutes. The times in the table are indicated from the moment the thermometer was turned on (5 minutes after placing it under the arm).
All thermometers accurately measure the body temperature in the armpit, but it does not take 10 or 60 seconds, as they say on the package. Both mercury and digital thermometers take 10 minutes for accurate measurements. If the body temperature rises significantly, the measurement may take place faster.
I did not notice any difference in measurement speed for different thermometer models and the promise of ultra-fast measurements for an expensive model turned out to be just an earlier sound signal.
At normal body temperature (36.6 ° C), immediately after the signal, all thermometers showed significantly underestimated results.
The method with the preliminary placement under the arm for 5 minutes of the turned off thermometer is quite efficient, after turning on thermometer and sound signal, the value of the displayed temperature is close to reality, and the measurement takes about 5.5 minutes.
© 2021, Alexey Nadezhin
For ten years I have been writing every day about technology, discounts, places of interest and events. Read my blog on the site ammo1.ru, at LJ, Zen, Mirtesen, Telegram .
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Lamptest.ru. I test LED lamps and help figure out which ones are good and which are not so good.
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