Stopwatches calibration

A stopwatch is a handheld device used to measure a specific time. Time will be calculated from the moment the watch is activated until the user presses the stop button.

A stopwatch is an important tool in the scientific field, allowing researchers to accurately measure time intervals in experiments. By providing precise timing, stopwatches contribute to accurate data recording and reproducibility of experiments. In this article, we will explore the different applications and benefits of using stopwatches in scientific research.

- Stopwatch helps make learning more focused

- Stopwatch is helpful for gym and exercise

- Stopwatch supports the cosmetic operation process

- Accelerate work progress quickly.

4.2 Calibration conditions

When performing calibration, the following environmental conditions must be ensured:

• Temperature: (23 ± 5) oC;
• Humidity: ≤ 80 %RH.

​4.3 Prepare calibration

Before performing calibration, the following preparations must be performed:

- Place the stopwatch in the calibration environment for at least 30 minutes;

- Calibration means must be powered and warmed according to technical specifications;

- Calibration tools and stopwatches must be placed in a location with little vibration and away from sources that generate electromagnetic fields.

4.4 Perform calibration

4.4.1 Initial inspection

External inspection must comply with the following requirements:

- The stopwatch must have clear signs and codes;

- There is no external damage that affects the watch's functionality;

- The electronic stopwatch must be displayed, fully, and without loss of focus;

- Mechanical stopwatch, the indicator needle is not bent or stuck, and the dividing lines are clear and sharp. The winding mechanism must function normally.

4.4.2 Technical inspection

Technical inspection must comply with the following requirements:

- For mechanical stopwatches:

+ Must wind up before performing inspection operations;

+ Press each key at least 5 times: the clock must operate normally.

- For electronic stopwatches: Press the Start, Stop, and Clear keys at least 5 times: the watch must operate normally.

4.4.3 Measurement inspection

Stopwatches are checked and measured according to the following sequence, content, methods, and requirements:

- Place the stopwatch on the measuring sensor of the stopwatch calibration standard;

- Set the stopwatch calibration standard in the stopwatch calibration mode corresponding to the mechanical or electronic stopwatch model;

- Read and record the results on the display of the stopwatch calibration standard (Average error of the electronic stopwatch) 15 times into the table.

4.4.4 Estimate the measurement uncertainty

- Time error of calibration

- Measurement uncertainty components (MU) of the calibration.

4.5 General handling

- After calibration, stopwatches are stamped and issued a calibration certificate with calibration results.
- Recommend calibration cycle: 01 year