- Electrical Instrument
- Sonic Toothbrush
- Digital engine analyzer
- Environmental Meters
- Non-contact voltage tester
- Digital tachometer
- Insulation Resistance Testers
- Ground resistance meters
- Other electrical test equipment
The earliest wind measurement case: the wind chicken
wind direction detection from when to start?
the people in the world there is always a concern for many aspects, and these ways, the wind observation is one of them, and the direction of the wind vane and so on products, bags, wuhan is in order to observe the change of wind speed, and in many cases, people can feel the wind, but don't know where you come from wind, also don't know the wind speed on the measurement of how fast, many of them are based on feeling to do, but these hardworking people can't stop, people in all aspects of the study with the wind.
people have long about jersey wind instruments, speak a lot of people don't believe that, as early as the 6th century BC, the Greek people with the chicken to measure wind speed, but also used to all the house where they put the wind vane, because the production of initial shape is like a chicken, so called the chicken, but it was not until 1797 that had the meteorologists to research the principle of wind chicken, also began to make further, more detailed.
in our case, in the western han dynasty have a device that is similar to the wind measurement, is made of feathers fall direction to determine the direction of the wind, the subsequent zhang heng also invented a kind of similar to the chicken of the copper birds, on the ground of the empty set on a pole, install a copper bird, can turn the above people, that is, according to the ability to identify the direction of the wind. Now there is also the near the runway to tell the pilot the wind on the ground, also contribute to the safety of the aircraft take-off and landing, the wind can put the bag it, also explains the strength of the wind on the ground.