Komputer tips

The circuit above can control speed of your DC motors or Computer Fans.If you use this to control speed of DC motors please use a diode to protect the Transistor,brush-less fans -OK.You can change the variable speed range by changing the value of R1 potentiometer.But don't use very high values,its pointless. The transistor used here is a NPN 2n3055,it can handle up to 15A and 115W of power.And this transistor can handle up to 60V.So if you're using this for PC fans you can add more in parallel.Normally a computer fan uses about 0.4W of power.Some powerful ones may use about 7W of power.If you don't use so much power then you can use a low power transistor like C1061,D313 etc. If you don't want to change the speed too often or hard to find a potentiometer or just willing to make this out of scrap you can use a Trim resistor for R1. The transistor may heat up very much and its essential to use a Heat sink.If you can,do not solder the transistor to the PCB s

Actually these are temporary files so the title should have been how to delete temporary files in Windows 7.Now windows 7 is getting older and older so it has to download so many updates from Microsoft to work with latest softwares and devices.When you set to update and install drivers automatically in wondows 7 it will download all the updates needed and install them,you don't have to worry.But the problem here is windows forgets to delete those files after installing them so a large number of unwanted files are saved in your system you don't even know! So we have to delete those temporary files.Its very very easy and you don't need any DOS skills or any programming knowledge.But before deleting those files I think that you can save those files somewhere else on a USB drive or a DVD to use them later.So you don't have to download update files every time you re-install windows.Or you can use these files to update your friends PC![Never tested though] Now lets get

When you work with electronics PCBs are very important.They are essential for circuits.PCBs have so many benefits than strip boards and dot boards and they last longer.Before going any further if you need to design your PCB from circuit schematic read our article on PCB Designing With Eagle CAD to design your PCB like a pro. In this article I'm going to teach you how to make PCBs using toner transfer method.This is very easy if you have all the materials at home.If you have a laser printer at home its going to be more easier.But before printing the PCB you need to edit the .ps file you printed using EAGLE CAD CAM processor to make more copies and get the most from your papers.To do so you need a photo editing software like Photoshop and GIMP.Let's get to work. Editing .PDF files for toner transfer print out ps2pdf.com and convert your files to .pdf first.You can also use any other online or offline converter.But DO NOT change any DPI values or page sizes. #2.Open Ado