A power supply is used to operate the electrical power for the equipment that may not be connected directly to the 220V socket, but require a different voltage, typically much lower, similar to that provided by batteries.
To make sure that the alternating voltage provided in the outlets of the house be equal to that of a battery, the power supply uses several components, each with a specific function: we will see what are these components, examining the construction of the simplest of the power supplies. Continue reading “How to build a Power Supply”
The term “LED” is an acronym that stands for “Light Emitting Diode“. The LEDs are constituted by a P-N junction realized with gallium arsenide or gallium phosphide, both of materials able to emit light when they are traversed by an electric current; the value of this current is between 10 and 30 mA. Continue reading “LED Diode”
On the “The diode as rectifier” there has been a talk of the inversely polarized diode behavior; it is seen that, by applying a positive voltage to the cathode than the anode, a current flows only very weak, said “drift current“, until the applied voltage reaches a value such as to trigger the “avalanche effect“. Working in such conditions, a normal diode comes early to destruction by overheating. Continue reading “The zener diode”
Telecommunications means remote transmission of information.
At the dawn of human civilization, to communicate was used smoke signals, the mirrors that reflected the sun’s rays, then the couriers on horseback, pigeons, and so on, but you can really talk about long distance transmission of information, both well as on cable, only with the invention of the TELEGRAPH and the MORSE code occurred in America in 1837 by Samuel Morse, painter and inventor, which allowed to transmit signals with a dot and line code through the prairie of the Wild West by using a single copper wire supported by wooden poles. Continue reading “The Origins of Telecommunications”
SSH (Secure shell ) is a UNIX based command line and protocol for remotely connecting to the machines in a secure way. Authentication process it is validated via a digital certificate from both sides.
Ssh can be used to connect from cross platform FTP like filezilla, winscp etc avoiding connecting In a non secure way via ftp, so in this way we can upload, download files from the web server without getting hacked.
Ssh secure the connection via symmetrical, asymmetrical encryption and hashing. Continue reading “SSH Protocol”