I have a electronic device that says it should be powered at 10 - 24 V 300mA max  I have a power plug witch outputs 12 V 1.1 A  Can I connect the plug to the device ?  Somebody told me I can if is true :  Why is that ?
Power supplies are available in a wide range of voltage and current ratings.  If I have a device that has specific voltage and current ratings, how do those relate to the power ratings I need to specify?  What if I don't know the device's specs, but am replacing a previous power supply with particular ratings?  Is it OK to go lower voltage, or should it always be higher?  What about current?  I don't want a 10 A supply to damage my 1 A device.
It seems like maybe cancelled downvote might be less...weird? Can we get some consensus on what flag to use for link only answers? Related:  (not a dupe, that's a feature request and was closed as a dupe of another one)        (old) post does indeed say that Link-only answers can be flagged as NAA, but there are a lot of posts like  which define Not An Answer is a way that it doesn't apply to link-only answers.  Can we get some up-to-date consensus on this? That link only answers are not allowed is . A map is continuous if and only if for every set, the image of closure is contained in the closure of image As a part of self study, I am trying to prove the following statement:  Suppose $X$ and $Y$ are topological spaces and $f: X \rightarrow Y$ is a map. Then $f$ is continuous if and only if $f(\overline{A})\subseteq \overline{f(A)}$, where $\overline{A}$ denotes the closure of an arbitrary set $A$.   Assuming $f$ is continuous, the result is almost immediate. Perhaps I am missing something obvious, but I have not been able to make progress on the other direction. Could anyone give me a hint which might illuminate the problem for me? Undefined control sequence BibTex This is one of the BibTex entries giving the problem:  @ARTICLE{2015ApJ...808L..36B,    author = {{Bonnivard}, V. and {Combet}, C. and {Maurin}, D. and {Geringer-Sameth}, A. and      {Koushiappas}, S.~M. and {Walker}, M.~G. and {Mateo}, M. and      {Olszewski}, E.~W. and {Bailey}, III, J.~I.},     title = "{Dark Matter Annihilation and Decay Profiles for the Reticulum II Dwarf Spheroidal Galaxy}",   journal = {\apjl}, archivePrefix = "arXiv",    eprint = {1504.03309},  primaryClass = "astro-ph.HE",  keywords = {dark matter, galaxies: dwarf, galaxies: individual: Reticulum II, gamma rays: galaxies, methods: statistical, stars: kinematics and dynamics},      year = 2015,     month = aug,    volume = 808,       eid = {L36},     pages = {L36},       doi = {10.1088/2041-8205/808/2/L36},    adsurl = {http://adsabs.harvard.edu/abs/2015ApJ...808L..36B},   adsnote = {Provided by the SAO/NASA Astrophysics Data System} }   and corresponding bbl file giving the error at compilation is  \bibitem{2009ApJ...697.1071A} {\sc W.~B. {Atwood}, A.~A. {Abdo}, M.~{Ackermann}, W.~{Althouse},   B.~{Anderson}, M.~{Axelsson}, L.~{Baldini}, J.~{Ballet}, D.~L. {Band},   G.~{Barbiellini}, and et~al.} \newblock {\bf {The Large Area Telescope on the Fermi Gamma-Ray Space Telescope   Mission}}. \newblock {\em \apj}, {\bf 697}:1071--1102, June 2009.   My guess is that Kile doesn't like references of the form 2015ApJ...808L..36B since these are the only ones giving the error.    Can somebody hint me to the problem in this? Thank you very much What is the difference between user and service account? I would like to know difference between user and service account.  I know that e.g. Jenkins installed to ubuntu is not a user, .    What is use of service account? When we need them? How can I create service account? Realtek RTL8723BE Wi-Fi incredibly weak I have a HP 14-AN001NA laptop. It came with Windows 10 installed on which the Wi-Fi worked fine anywhere in the house.   However I removed Windows 10 and installed Ubuntu 16.04 instead and since I have had terrible Wi-Fi anywhere aside from about three foot away from the router. I don't know if it's relevant but my Wi-Fi is not called wlan0 but wlo1 for some reason (I didn't change it).  When running lspci -knn | grep Net -A3     I get the following output:  05:00.0 Network controller [0280]: Realtek Semiconductor Co., Ltd. RTL8723BE PCIe Wireless Network Adapter [10ec:b723] DeviceName:   Subsystem: Hewlett-Packard Company RTL8723BE PCIe Wireless Network Adapter [103c:81c1] Kernel driver in use: rtl8723be Kernel modules: wl, rtl8723be When I type $\overset{\circ}{Z}^\lambda$ the lambda is placed slightly above and to the right of the circle. Is there a way to make it appear as a superscript on the Z? I tried $\overset{\circ}{Z^\lambda}$, but then the circle is too high and to the right.  As a bizarre aside: a friend uses the exact same code with no problem. However, when I type it into MathOverflow it looks the same as in my compiler (i.e. bad). Prevent users from submitting a form by hitting Enter I am just starting out learning mathematical induction and I got this homework question to prove with induction but I am not managing.  $$\sum\limits_{k=1}^{n}{\frac{1}{\sqrt{k}}\ge\sqrt{n}}$$  Perhaps someone can help me out I don't understand how to move forward from here: $$\sum\limits_{k=1}^{n+1}{\frac{1}{\sqrt{k}}+\frac{1}{\sqrt{n+1}}\ge \sqrt{n+1}}$$ proof and explanation would greatly be appreciated :) Thanks :)  EDIT sorry meant GE not = fixed :) How to group distinct values from a list using odata rest api 6-digit password - a special decoding method Definition of Significant Figures In my textbooks,  are defined as:   “Significant figures by definition are the reliable digits in a number that are known with certainty.”  “A significant figure is the one which is known to be reasonably reliable.”    Reliable means giving the same result on successive trials or reliable information can be trusted to be accurate. However, at the end of each of the two definitions it is also written that ‘the last digit of a number is generally considered uncertain in the absence of qualifying information.' For example if the mass of an object is 12.248 gm, the last digit which is ‘8’ is uncertain by plus or minus 0.001 gm. This uncertainty is unreliability in the information. So, the digit ‘8’ is uncertain, and thus according to the definition 1 it is not a significant figure. However, the rules for significant figures say that ‘non-zero digits are all significant’. Due to the last digit ‘8’, if the object was weighed with careful handling minimizing the chances of error, the figures preceding ‘8’ that are (1, 2, 2, 4) are certain and reliable. If the mass of another object is 2 gm, then it is uncertain by plus or minus 1 gm i.e. its mass could be 3 gm or could be 1 gm.  ‘2’ is therefore not certain! What is the reason that significant figures are defined to be the reliable digits in a number? In what sense they are said to be reliable? So I need to compress a directory with max compression.   How can I do it with xz? I mean I will need tar too because I can't compress a directory with only xz. Is there a oneliner to produce e.g. foo.tar.xz? I want to use VBScript to catch errors and log them (ie on error "log something") then resume the next line of the script.  For example,   On Error Resume Next 'Do Step 1 'Do Step 2 'Do Step 3   When an error occurs on step 1, I want it to log that error (or perform other custom functions with it) then resume at step 2. Is this possible? and how can I implement it?  EDIT: Can I do something like this?   On Error Resume myErrCatch 'Do step 1 'Do step 2 'Do step 3  myErrCatch: 'log error Resume Next What is the inverse function of $e^x +x$? "Started to work" vs "Started working" Intuituive reason why Fermats last theorem holds I am unsure of whether it is normal, but to me, intuitively Fermats last theorem should not hold.  If anyone intuitively believed it to be correct, why?     Can someone explain so I understand somewhat why FLT holds without reading a massive and complex proof? $g^k$ is a primitive element modulo $m$ iff $\gcd (k,\varphi(m))=1$ Leaving Italy without paying a bus fine My wife and I got bus fines today in Bologna. We had only recently arrived and had purchased a ticket from where we were staying which was about 6 or 7 km from the city. The hotel receptionist explained the ticketing system to us and said that if we buy a ticket we could use it on as many journeys for 75 minutes.  We took the bus from our hotel to Bologna and then straight away got on another bus to get to central Bologna where all the sights are. When we got on this other bus we assumed that it was ok as we were still within the 75 minutes. However, when we tried to validate our tickets in the machine it flashed red like an error had occurred so we figured something wasn't right.   We tried to ask the driver about it or if we could buy a ticket but he just grunted and started to drive off. We therefore started to leave the bus at the next stop so we could try and buy another ticket but were ushered back on by a few men who turned out to be ticket inspectors!  They alleged that our tickets were not valid in the city and that we had to pay a 65 euro fine. They wanted to see our official documentation and so took details from our UK driving licences and issued us both with fines. They wanted us to pay there and then, but we explained we didn't have enough cash on us to do so and they then stated we could pay by card.   However, I still wasn't happy about doing that so he then said that we could pay later by going to an Italian post office; or if we don't pay within a certain time the fine will go up to 270 euros each and will be posted to us (he got our addresses off our UK driving licences)!  I am a bit miffed about this as we were noway trying to evade and as soon as we realised our mistake we tried to talk to the bus driver to buy a ticket or get off the bus, but he drove off and ignored us! I have a slight suspicion that it was a rouse as it is very strange that he did this and then out of nowhere bus inspectors got on and made a beeline for us!  If we go back to the UK without paying these fines and ignore the subsequent fines that they send us through the post (if they do send any), then what happens? Do they have any powers when we are back in the UK? a total fine of 500 euros for an honest mistake seems utterly outrageous.   Fine below Sex worker student offering her (lawful) services One of my students is an escort/stripper and she has offered me (and other faculty in my department) her "services". I am pretty sure my initial reaction of "thanks for letting me know, now can you answer the question about how to calculate the standard deviation", may not have been the best reaction. The offers have continued. My head of school is aware of the issue, and has asked if I want him to do anything.  Is the student doing anything wrong by offering her services to me? For what it is worth, prostitution is legal in the UK. Is this any different then a student telling me she works in a restaurant?  What is the correct response in a situation like this?