Logic Families in Digital Electronics - TTL, CMOS, and ECL

Most electronic systems which are responsible for modern advances are based on digital technology. All digital systems, computers and microprocessors are assembled from simple circuits called logic circuits. The basic building blocks of logic circuits are logic gates. And logic gates themselves are simple electronic circuits comprising of diodes, transistors and resistors.

Wiring Materials And Installation Methods in Electrical Construction Works

Electrical wiring needs expertise attention to every building projects. It directly related to the safety of human beings and utilities / equipment people handle. The scope of electrical wiring shall cover supply, installation, testing and commissioning of all conduits and accessories, wiring, switches, socket outlets, spur outlets, junction boxes / pull boxes, GI pull wires, ceiling roses making connections etc. This Electrical Construction Article gives comprehensive details of various installation methods, materials used in each installation methods used in building construction projects.

Typical Cable Laying Details For Direct Buried, Low Tension Cables

Most Construction projects requires underground cabling system for its power supply, some times High tension system too. The architects and builders are least bothered about how this cables routed to the premises and equipment. If electrical professionals pointed out the feasibility, the aesthetics of the project would touch to the intended level. Hence, in the planning stage itself the routes and size of the power cable trench to be incorporated in the project design.

Method of Earthing or Grounding for Diesel Generator Plant

Earthing or Grounding of Diesel Generator Plant is important to ensure correct operation of the plant and safety of the people who work over there. Generator neutral (star point) is to be connected by insulated earthing conductor through the neutral earthing link or device to main earthing bar. Neutral earthing conductor is to be suitably sized to carry maximum earth fault current for time it takes the system protection to operate with final conductor temperature not exceeding 160 deg. C, but not less than 30 mm2 per 100 kVA of generator rating, with a minimum of 50 mm2. All emergency power diesel gensets including portable gensets to be connected to grounding conductor.

Also read: Guidelines for installing emergency power diesel genset.

Testing and Commissioning In Electrical Construction Works

At the completion of the electrical installation works, the entire installation shall be subject to the test before final placing in service under the full responsibility of the contractor. Unless Otherwise specifically called for all tests shall be carried out in conformity with IEE regulations. Contractor shall coordinate with the Client and the Supervising Engineer to get electricity from the local supply authority before starting of testing and commissioning.

Mechanical, Electrical, Plumbing (MEP) in Construction Contract

The acronym MEP became an integral word of a building project in Middle East Gulf region during year 2000. In the inception stage of MEP, there were involvement of only two engineering branches, Mechanical and Electrical, now it included electronics, instrumentation and communication. In some occasions, Mechatronics also partake in the project for smooth completion of the whole MEP works. Companies that carry out MEP works also known as Electro-Mechanical company which has multi-faceted technicians and engineers for effective design, coordination and execution of the works.

Typical Installation Details Of Floor / Wall Mounted Electrical SMDB

Electrical Sub-Main Distribution Boards (SMDB) are the integral part of Electrical LV Power distribution network in the end user premises of a medium and large scale projects. SMDB acts as a mediator between Main Distribution Board (MDB) and Final Distribution Boards (FDB) that serves approximately 100A to 400A load range.

Method Statement For Installation Of Electric PVC Conduits And Accessories

Method Statement For Installation Of Electrical PVC Conduits And Accessories In The Concrete Slabs, Columns, Block Works And Concrete Walls

1. Introduction and Scope

This method statement explains the detailed requirements and procedures for the installation of PVC Conduits and accessories in the concrete slabs, columns, block works and concrete walls.

Method Statement For Installation Of Cable Tray Or Trunking

Electrical Engineers seldom show interest acquiring knowledge and experience on cable tray installations. Most of them think it's a concern of mechanical fabricators to be taken care of it. A proper and professional way of cable tray installation requires good involvement and coordination of people from both electrical and mechanical disciplines. If cable tray system has been installed appropriately in a project, following advantages can be counted:

  • Cable Tray system enhances safety of electrical wiring system.
  • Cable tray installation provides dependability in any circumstances.
  • Cable Tray system saves space, materials, labor, time and cost.
  • Maintenance and extension of cable tray installation are easier than any other wiring system.

Hence, electrical installation of a project must give high priority to adopt properly evaluated cable tray wiring system if aesthetic impact is low. This article explains how to make a typical method statement for cable tray or trunking installation for a building project.

Low Voltage (LV) Power Cables In Electrical Construction Works

The scope of work shall cover laying, connecting, testing and commissioning of low voltage power cables complete with all cable support, cable, cable trays, clamps and joints. Cables to be purchased from who regularly engaged in the manufacturer of electrical cable and wire products of the types and ratings required, whose products have been in satisfactory use in similar service not less than 5 years. The standard of the cables shall comply with National Electrical Manufacturers Association of local standards or any other approved.

Electric Appliances

First of all, we have to look into what is the definition of Appliance in-general and specifically for Electric Appliance.

Definition of Appliance

What is the definition of Appliance? The term appliance can be defined as, "a device or apparatus or equipment designed to perform an application or task, other than industrial, benefited in our personal life that uses some kind of technology". In short, an appliance is a machine that reduces a human’s effort in carrying out a specified work or task. For example, a scissor uses to cut our hair, an iron box to ironing our clothes, a TV to watch entertainment programs and news form different parts of the world. Here, scissor uses mechanical technology to perform its function. It uses only mechanical energy that generated by parson it operates, where as, other two appliances use electricity as the source of energy to operate it. Appliances may be indoors or outdoors, fixed or portable or hand held or hand operated or remotely operated or computer controlled and there on.....

Method of Lightning Protection System For Building

Comply with the General Conditions, Supplementary Conditions and the requirements in various Sections of the Electrical Specification. In addition read and conform to all Electrical Sections of these specifications. The installation shall comprise air networks connected to roof and down conductors and finally terminated in earth electrodes, via structural re-bars and suitable test points in accordance with the details included on the attached drawings or in the Specification Section.

Conduit Wiring In Electrical Construction Contract Works

Scope of Work of this this sample specification covers the supply, installation, testing and commissioning of all wiring materials for power and lighting in concealed and/or surface conduits.

1. Applicable Standards

The conduits shall conform to IS 9537 I & II  or equivalent standards. Switches, Plug Sockets shall conform to IS 3854 and IS 4615, however, contractor shall comply with the latest or superseded versions of IS/BIS to be used for the complete work.

Method of Clean Earthing or Grounding in Electrical System

Clean earth grounding or low noise earth shall be provided as required, to ensure that the level of induced or conducted interference from external sources, including the facility power grounding system, does not produce incidence of malfunction of the equipment, which is unacceptable for the operating system. The electronics systems must be protected by providing a network path having low impedance for interconnecting its equipment.

Proper routing, zoning and shielding of the cables / earth wires are important and must serve the purpose of preventing sources of electrical disturbances from the operation of electrical equipment.

General Questions And Answers In Engineering and Technology

What Is Engineering? Engineering is an art of applying science to the optimum conversion of the resources of nature to the uses of humankind. It is based principally on physics, chemistry, and mathematics and their extensions into materials science, solid and fluid mechanics, thermodynamics, transfer and rate processes, and systems analysis. It is thus we must define Engineering: "the practical application of science and math to commerce or industry". In other words "the art or science of applying scientific knowledge to practical problems".