Hello, my name is Keeter. I'm going to give a brief introduction of drivers gobs. To begin with, what is a drivers gob, and how does it work? A drivers gob is a device used to measure angular velocity. Let's take a look at this device. You can see the drivers gobs spinning steadily at any tilt angle, and this match called phenomenon is attributed to the conservation of angular momentum. In a figure, you can see the inside spinning wheel has an angular momentum in this direction, and a griptop 4-skips of torque in that direction. In order to increase the angular momentum to the vertical direction, we'll change the spinning axis and make the drivers gob rotating. And this is the basic concept of the mechanical drivers gobs. In applications such as airplanes, when they have a tilt angle, the drives gob will maintain a spinning position. So we can measure the angle variation. However, the mechanical drives gobs have disadvantages, such as friction effects and measurement errors. So there are two different advanced drivers gobs, which I will illustrate next. First, I will focus on optical drives gobs, and let's look at this animation. This is a bin splitter, which allows some protons go through it and some will reflect instead. Then the bins will reflect through mirrors. Normally, these protons will arrive at a sensor simultaneously, but when we rotate the device, the device will be able to see the difference between the two. Surprisingly, one will arrive first, and this is called segment effect. Optical drives gobs are based on measuring the two bins' phase differences when the drives gobs have an angle change, and there are two common kinds of optical drives gobs, one is the relayed drives gop, which have the same concept of the animation. And the other is the fiber optic drives go, which replace the mirrors with optical fibers. This device improves the accuracy by excluding the influence of friction, vibration, and etc. Also, there are light and durable, so they are immensely applied in aircrafts and satellites. Okay, that does move on to another type of drives gop, the MEMS drives gop. There are various kinds of MEMS drives gop, but I will discuss two major kinds of them, one using capacitors, and the other one applying piezoelectric materials. Let's look at this capacitor structure. There is a mass, and there is a driving force, and when there is an angular change, the query already has effect happens. Which will force the structure to move in this direction when the driving force is to the right? And more force the structure to move in that direction when it is to the left. And due to this equation, when the distance changes, the voltage across the capacitor will change, so we can convert the voltage change into an angular variation. And this kind of drives gop are often used in smartphones. On the other hand, as for piezoelectric ones, the structure can be also designed as applying the query already as a fact, which I will not describe again. But they can also be designed as the ones similar to the figure. When there is an angular variation, stress will be applied on a piezoelectric material. According to the property of the material, it's surface stress will generate electric potential, which we can convert into angular variation. And they are usually used for measuring vibrations. Although MEMS drierscopes are now accurate at optical ones. They are achieved and widely used. To sum up, drierscopes can be seen in many electronic devices, combining with S-orometers and geomatic sensors. Therefore, it is a really useful gadget for us to understand how it works. Thank you for watching the video and I hope you learned a lot from it.