In this video we explore the control board inside a DVD player. Created by Karl Wendt.
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- @1:14What causes the quartz crystal to respond this way to either mechanical or electrical action? Is there a name for this effect? Are there other materials used in elsewhere or existing in nature that exhibit this property?(19 votes)
- at 2.30 ...there is only one chip for audio and video processing and after processing why they are separated and transmitted using different ports(2 votes)
- The audio signal is headed to the speakers. The video signal is headed to the monitor display screen. Different signals headed to different places often take different paths.(7 votes)
- how dose quartz crystal have power in it when it's squeezed(3 votes)
- This is due to something called the piezoelectric effect. I'm guessing that a full understanding of it would involve a lot of physics and math, but a basic explanation is that when mechanical stress is applied to the crystal, it produces an electrical charge. Try googling "Piezoelectric Effect", maybe you can find some more detailed explanations that aren't too mind-explodingly technical.(2 votes)
- How would you know this stuff?(2 votes)
- why is there so much stuff on a tiny board(1 vote)
- I'm taking apart a circuit board and it's got A red rectangular plastic piece with the number225J400MPP any idea what it is?(1 vote)
- [Instructor] Okay, so this is our microcontroller board, and let me move the plug here, let's see if I can take some of these plugs out, so the power comes into this board through these two plugs here, and flows to this socket here and this socket here. And there are a number of different components and chips on this board, we're gonna talk about each of them and sort of what they do. Now, in full disclosure there's certain components I'm not 100% sure what this chip does, but I think I know, so we'll go through that and we'll make the best guess that we can. So this I believe is an EEPROM, which is an erasable memory chip an electrically erasable, programmable memory chip that stores an index of commands for this board even when the power's shut off. So this chip right here, which is the Central Processing Unit chip, and controls all the functions of this board as well as the functions of the entire unit, this chip basically can go and pull indexed commands from this as, you know, it sort of acts as its memory. And then this is the clock chip. So this one has a little quartz crystal in it, and quartz has an interesting property. When it is squeezed, it can emit a small electrical signal or when electricity is run to it, it will expand just slightly. And so because of that, it's very consistent in the way that it responds to electricity and very consistent in the way that it expands and so because of that property, they're able to run electricity to it and get it to expand and get a return voltage and then they can determine this device here can allow the chips to determine a very precise timing. It's the same type of timer that's inside of a quartz wrist watch. But anyway, it allows this board to synchronize itself which is really important when you're reading a lot of data from a disk and you have to make sure all those ones and zeroes end up in the right place and everything happens in sync. So that's very important there. As I said before this is the central processing chip that controls the board and the functions on the board, I believe this chip is the video and audio processing chip so once the data comes in, it's routed through the CPU, to this, and processed and converted into a signal that your TV and stereo will understand. I believe this chip is an Op Amp chip, which basically stands for Operational Amplifier and it will boost the signal coming out of this chip. So this chip's signal may be very weak, and in order to get it to travel down the cords to go to your TV and your stereo, you need to boost the signal, increase the voltage, and that's what this guy can do. And this chip right here is a motor controller. And so what it does is it controls the direction and speed of the motors, and it does that in a very precise way, so it works with the CPU to make sure that the motors are moving in the right direction and at the right speed.