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-   -   Analog volume control, digital volume control (http://www.physicsforums.com/showthread.php?t=454720)

 jackson6612 Dec7-10 05:19 PM

analog volume control, digital volume control

I'm not a science student; have some basic knowledge of it. So, please explain in as much detail as possible. Thanks.

I have seen some old TV sets with a round knob to adjust volume. A guy told me that it's an analog volume control while the new TVs come with digital volume control where you adjust it by pressing a button. Is it true? What are the advantages of using digital over analog in this case? Isn't analog a good choice? Why? Because I suspect a digital control can only go from one fixed value to another fixed with no midway value. e.g. you can get from 2 to 3 to 4 but not from 2 to 2.5. But an analog gives a lot of flexibility between any two values. By the way, I don't know how these things work, just guessing.

 NobodySpecial Dec7-10 05:50 PM

Re: analog volume control, digital volume control

Quote:
 Quote by jackson6612 (Post 3025337) I have seen some old TV sets with a round knob to adjust volume.
Yes - it's a potentiometer = a variable resistor.

Quote:
Cheaper, the potnetiometer costs more than a button and it's difficult to remote control.
Although I have an expensive amplifier where the remote control drives a motor which turns the volume knob.

Quote:
 Isn't analog a good choice? ... But an analog gives a lot of flexibility between any two values.
In theory yes, but in practice there is a limited amount of quality in the audio signal (especially on a TV) so if there is 0.5 units of "noise" then being able to adjust form 2 to 2.5 is a bit pointless. You can always make the digital control to go up in 0.1 unit steps if you like.

Another reason for the digital is that the potentiometer is noisy when it is being turned (at least on cheap ones) so you get a crackle or hiss as you adjust it which people dislike.

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