Variable Frequency Drive
Variable frequency drives are widely used to control the speed of ac motors. This note looks at the mechanisms which enable drive units to control the...
LED Replacement Light Bulb
The inventor of the first visible light-emitting diode makes history again this year as it begins to show customers a 40-watt replacement GE Energy Smart...
Earth Electrode Resistance
Earthing of electrical systems is essential for the correct functioning and the protecting of life and equipment in the event of faults. The earth electrode...
Lightning Risk Assessment (IEC 62305)
IEC 62305 'Protection against lightning' requires a risk assessment be carried out to determine the characteristics of any lightning protection system...
Photovoltaic (PV) Panel - Performance Modelling
In an earlier note on the site [Photovoltaic (PV) - Electrical Calculations], the theory of solar (PV) cell calculations was introduced. In particular...
Operational Amplifier
The fundamental component of any analogue computer is the operational amplifier, or op amp. An operational amplifier (often called an op-amp,) is a high...
ANSI (IEEE) Protective Device Numbering
The widely used United Sates standard ANSI/IEEE C37.2 'Electrical Power System Device Function Numbers, Acronyms, and Contact Designations' deals with...
E-Ink
Before the technical, some general information. E-ink display are found in a lot of e-readers, some mobile phones and similar devices and the intent is...
Periodic Electrical Installation Inspection – How Often?
How often installations are inspected is up to the owner of the installation, provided such durations do not exceed any regulatory maximums in force. ...
Closed Doors
"I can live with doubt and uncertainty and not knowing. I think it is much more interesting to live not knowing than to have answers that might be wrong...