Mobile Phones (Brick to Implant)
The mobile phone was born in 1973. They were the size of a brick and weighed a couple of kg, making them difficult to fit into your pocket. At a few thousand...
Switchboard - Forms of Internal Separation
IEC 61439 'Low-voltage switchgear and controlgear assemblies', specifies standard arrangements of switchboard (call forms of internal separation). The...
1,000 kV UHV First for China
At the beginning of the year China put the world's first 1,000 kV UHV transmission system into operation. Transmitting power at over a million volts is...
Control Theory
Control theory looks at how systems work and are controlled from a mathematical view. This note gives a brief introduction to some of the concepts – more...
MIT OpenCourseWare
MIT OpenCourseWare, makes the materials used in teaching all MIT subjects available on the Web, free of charge, to any user in the world.
Questions - Reputation and Privilege
Our question and answer system while letting you do exactly what it says, is much more. It is a dynamic user driven system, where our users not only ask...
Electrical Engineering
Electrical engineering is a field that covers a wide variety of sub-fields, including electricity and electronics. It is a field that goes back to the...
Voltage Drop in Installations - Concepts
Problems on achieving maximum voltage drop within an installation come up often. Depending where you live, local regulations will have different limits...
Power Factor
Power factor is the ratio between the real power (P in kW) and apparent power (S in kVA) drawn by an electrical load. The reactive power (Q in kVAr)...
Batteries
A battery consists of one or more cells, each of which use stored chemical energy to produce electrical energy, There are many types of cells and these...