Wikipedia:Reference desk/Archives/Computing/2016 July 22

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July 22

Oscilloscope

Is it OK to test 220 volts AC on a single channel Oscilloscope ?124.253.247.191 (talk) 01:48, 22 July 2016 (UTC)

No it is absolutely not OK to test mains voltage on an oscilloscope, unless you know precisely what you are doing and what safety measures to take. If you need to ask here, don't do it. To answer the question, there are oscilloscopes that CAN be used on mains voltage, it should say on the scope, if you can't see a max voltage, or are uncertain how to read what is written on the scope, don't do it, seek assistance from someone with experience / qualifications. Vespine (talk) 02:05, 22 July 2016 (UTC)

(ec)Probably not. You should check the manual to see what the rating is. A knob on the front for adjusting the gain should also give a clue. Such a voltage is dangerous and could kill you, so you would need appropriate earthing and probe insulation. Instead you could put the mains AC through a step down transformer, say to 5 volts which is likely to be workable with your oscilloscope. Mains AC also has much higher voltage transients due to electric motors turning on and off, so the rating of equipment needs to be much higher to avoid damage. Graeme Bartlett (talk) 02:13, 22 July 2016 (UTC)

Live household electric wires at 220 volts can kill you. Do not work with live mains. Do not connect them to your test equipment.

For the most part, there is no good reason to hook up mains lines to an oscilloscope - that type of test equipment is normally used for analyzing much lower-power signals - it's rarely needed for analyzing power lines.

In the exceptional case where detailed analysis of high voltages or high power is required, a special probe called a current clamp is used. This allows a skilled engineer to investigate the high-power system without ever making electrical or physical contact with the mains wire. If you don't know what this is, or how to use it, call an electrician to help you. Death by electrocution is very easy when you're dealing with 220 volt mains lines. Death by electrocution happens very fast, is very unpleasant, and is generally irreversible, so don't play with wires if you have any doubts about the correct safety procedures. Nimur (talk) 03:52, 22 July 2016 (UTC)

Yes- death is usually irreversible! — Preceding unsigned comment added by 86.187.172.183 (talk) 20:25, 24 July 2016 (UTC)

Audio software

I have hundreds of film songs which are named as 001, 002, 003...and so on. I want to rename them such as the song file name should be the opening lines of the song. (e.g. If the song begins with 'oh my god' then the song file name should be oh my god.) Is there any software which can do this? Thank you.175.157.6.165 (talk) 03:00, 22 July 2016 (UTC)

There is software that compares a song against a large database and changes the title to the actual title of that song. It would then need to take an extra step of looking up the lyrics and renaming it as you say. Seems possible, but I doubt if it exists yet. Something else to consider is that the opening lyrics aren't always the most memorable. StuRat (talk) 03:29, 22 July 2016 (UTC)

Further, the opening lines of songs are often used repeatedly. I immediately thought of three songs that begin with "Hit me." That doesn't get into covers of songs that will obviously use the same lyrics. So, this tool will need to have a method to handle making file names unique when the opening lines are the same. 209.149.113.4 (talk) 12:50, 22 July 2016 (UTC)

True, but the actual titles are often reused, too, and they may or may not be remakes of the same song. For example, look at all the songs named "Maria". StuRat (talk) 14:08, 22 July 2016 (UTC)

SRMv2: System Restore Manager v2

1) The Disk Space to use for System Restore based on the top-right-hand-side of the software's window, the GB increments whenever I do a System Restore. Note: I don’t/didn’t install anything for quite some time now, and my Windows Update system is off.

2) Selected Fixed Drive drop-down-list of the Disk Space to use for System Restore section, is allocated in C drive. Where is this place located in the C drive, and, would it create problems if I delete files from this location?

Apostle (talk) 09:24, 22 July 2016 (UTC)

1) I suspect it is doing a backup of the backup. That is, the file it creates with the restore info is itself backed up the next time it is run. To avoid this, either the software needs to be smart enough to not do that, or you need to store the backup files some place other than the partitions being backed up. StuRat (talk) 14:13, 22 July 2016 (UTC)

I deleted the 'manual recovery point' than recreated it again, decreased a lot of GB but didn't make it zero; probably because there are two more early recovery points existing... -- Apostle (talk) 05:19, 23 July 2016 (UTC)

Crystal Oscillator

Please expand picture by clicking on it if you find numbers too small to be read

All my search on Google and at other places on the Net was only enough to ensure that the thing is a Crystal Oscillator, the numbers etc. on the top proved to be useless, was unable to find any data-sheet or even a pin-out diagram. The vendor, who (methinks) has no reason to lie, says it's a 16 MHz Crystal Oscillator (And that's ALL he knows about it). Can anyone please draw me its rough blue-print showing where and how to fit it in what type of circuit, power source be AC or DC and how much volts, what type of resistors (or other components like transistor(s) etc. ) should be fitted, and where. And how to bring its rate below 10 Mhz (if possible). Thanks 124.253.146.87 (talk) 15:30, 22 July 2016 (UTC)

Actual Shape (had to make two pictures because shape and markings, which are on it's top, can't be shown in single picture)

• Is the vendor a shady character in an ill-frequented bar? Otherwise, any info on who manufactured the chip would probably prove useful.
• :OP is in India, and has himself received Amazon(.in) and the regional Ebay packages full of nothing but old newspaper cuttings ! This happens when Amazon etc. is in no position to dispatch and hence directs one of its contracted vendors to deliver detailed item(s) to the address they provide.

I cannot claim to understand it all, but going by this, it would seem the "crystal oscillator" is a passive two-terminal linear electrical component and the frequency comes from the eigenmode. In that case, frequency cannot be changed (except by opening the case and replacing one of the components). Tigraan^{Click here to contact me} 16:08, 22 July 2016 (UTC)

It look remarkably like an MEC crystal oscillator, 16 MHz. 209.149.113.4 (talk) 16:37, 22 July 2016 (UTC)

This is MEC's website and this is their datasheet for this range of crystals. See crystal oscillator for our article on the general subject. The crystal on its own can't generate a signal, and you can't change the frequency of the crystal - you need to build a (16 MHz) oscillator using the crystal to control the frequency, and feed the output to a suitable combination of frequency dividers and multipliers to get the frequency you want. Tevildo (talk) 08:49, 23 July 2016 (UTC)

As far as the circuitry needed to make it function, that is all dependent on your ultimate goal. Crystal oscillators are simply parts of the puzzle the same as resistors, diodes, etc. What are you trying to make with that component? See here for more information. RegistryKey^(RegEdit) 05:02, 24 July 2016 (UTC)

I have used a crystal oscillator most frequently to drive the clock of a micro controller. You will always find one on an Arduino board, this one happens to also be 16MHz. The processor used in a Arduino is an ATMEL AVR, and here is a tutorial about how to connect a crystal to such a processor. The only additional components you require for such a task are called load capacitors. Vespine (talk) 01:11, 27 July 2016 (UTC)