Computing desk
< October 12	<< Sep \| October \| Nov >>	October 14 >

Welcome to the Wikipedia Computing Reference Desk Archives
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages.

October 13

Excel Score Sheet

I'm trying to develop a score sheet for the quizzes I run at a local pub. I'm having trouble setting up the results table that shows the first, second etc. place of each team.

At the moment, I'm using the LARGE function to find the largest, second largest etc. value in the total scores row, and then HLOOKUP to retrieve the equivalent team name for that value. So, for example, if scores are in row 11, and team names in row 12,

                G                                       H
15    =HLOOKUP(H15,A11:H12,2,FALSE)		=LARGE(A11:H11,1)
16    =HLOOKUP(H16,A11:H12,2,FALSE)		=LARGE(A11:H11,2)

will return the names of the teams with the largest and second largest scores into G15 and G16.

This all works fine unless there are ties. In that case, the function returns the same result in both cases. Am I going about this the right way, or is there a simpler solution? Rojomoke (talk) 14:07, 13 October 2016 (UTC)[reply]

You could use the RANK function (or, in newer versions of Excel, the RANK.EQ function) to show the rank of each team's score. See here for documentation. RANK assigns an equal rank to equal values - for example, scores of 20, 10, 5, 10 and 25 will be assigned ranks of 2, 3, 5, 3 and 1. Gandalf61 (talk) 14:37, 13 October 2016 (UTC)[reply]

Internet and W10- another change

My internet connection has suddenly gone back to using Wi fi via my Netgear adaptor, having previously connected via pseudo ethernet (NDIS over USB).I cant see the ethernet icon now. Whats going on here? Has Windows updated again to correct the previous fault? --86.187.170.237 (talk) 17:21, 13 October 2016 (UTC)[reply]

D.C. to A.C.

What is the best and easiest method of turning battery-level D.C. into A.C. Though not sure, I think it is done as a part of Tesla's high voltage generator that has only (mostly) a 9v D.C. as a source of the power. I think it just uses a transistor and a resistor. Can someone please explain a bit more lucidly the way they actually work. 124.253.249.170 (talk) 21:11, 13 October 2016 (UTC)[reply]

See Power inverter#Circuit description for our article on the topic and the section on circuits. "Best" depends on what you are trying to achieve: efficiency, cheapness, profit, reliability, heat dissipation, noise. Graeme Bartlett (talk) 21:24, 13 October 2016 (UTC)[reply]

Would help to know what you application is. Just a transistor and a resistor may be OK as a Joule thief for running LED's but other devices may need something a little more sophisticated.--Aspro (talk) 21:26, 13 October 2016 (UTC)[reply]

Use a DC motor to drive an AC generator might be the most simple way to understand but is causes huge losts. Understanding switching mode power supplies (SMPS) gives the basic for todays power inverters. Image a Class-D amplifier would not drive a speaker, but someting else instead. The input signal is a 50 or 60 Hertz sinus, syncronized by external reference. A transistor with a resistor have no phase delay, see Bipolar transistor biasing. Only long wires or large plates affecting the transistors base can make it become an oscillator. Inductive and capacitive parts delay voltage or current each other for bulding an oscillator. --Hans Haase (有问题吗) 09:04, 16 October 2016 (UTC)[reply]