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Electrical engineering
Course: Electrical engineering > Unit 9
Lesson 3: DVD playerWhat is inside a DVD player? (3 of 5)
In this video we explore the control board inside a DVD player. Created by Karl Wendt.
Want to join the conversation?
- @What 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? 1:14(19 votes)
- The piezoelectric effect is also used in ultrasound operations, i believe.(3 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)
- the internet or by using an awesome website like Khan Academy(1 vote)
- How many pieces are in this DVD player control board?(2 votes)
- why is there so much stuff on a tiny board(1 vote)
- To conserve space and thus conserve money.(2 votes)
- 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)
- how long does it take to build a DVD player.(1 vote)
- where did u get dvd player(1 vote)
- athe says "clock chip". it's not a chip, it's a compnent 1:15(1 vote)
Video transcript
- [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.