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.

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.....

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.

Installation of Structured Cabling For Voice / Data System In Building Construction

The Contractor shall design, supply and install outlet plates, conduits, trunking, trays, wiring, junction boxes, distribution frames, patch panels, data rack, backbone cables, etc. necessary to form a complete structured system for voice and data cabling within the buildings. Cabling / wiring shall be provided for voice system from patch panel location to each voice/data outlet. Draw wires shall be provided in conduits for future data cabling / wiring by others (if applicable). The installation shall comply with the requirements of ANSI / EIA / TIA-568-1991 as appropriate as well as Local Telecom Authority.

Voice and data outlet plates shall be designed to accept industry standard RJ45 plugs.

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.

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.

Lighting Distribution Boards (LDB) In Electrical Construction Works

Lighting Distribution Boards (LDB) are an integral and essential part of every building project and it must be designed, manufactured and installed all in accordance with the safety standards. In most of the cases it operates a layman wherein others operate dedicated or trained person. This article explains what are the essential standards, parts, frame to be applied for manufacturing and installation of lighting distribution boards in a quality building project.

Electrical Earthing or Grounding For Metallic Fencing

Compound Demarcation or separations of compounds may use metallic fences sometimes for saving money or aesthetic reasons. Architects and owner of the project decide whether their property protected by compound wall or it needs only fencing. If fencing considered, most cases it will be metallic fence. In the electrical point of view and as a safety measure, metallic fence shall be separately earthed unless they come within 1.8 m of any equipment or structure above the surface of the ground, which is connected to the main earthing system. If the separation of 1.8 m cannot be obtained the fence shall be bonded to the earthing system. Here is how compound fences connecting to the earthing system.

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.

Method Statement in Construction Contracts

Every project is unique, in particular, construction projects. There are many methods applied to accomplish functioning of individual installations included in the whole project. Building services like Mechanical, Electric, and Plumbing (MEP) work have given more importance than other disciplines dealt with. It's because of complexity and alternate methods available to accomplish the same output. While executing individual installations - also known as tasks - construction team have to adopt suitable methods submitted as an integral part of Tender. Most of the project managers or representatives of client keen to look Method Statement of critical and important tasks. We will look into what is Method Statement and what is the importance a Method Statement brings to a construction project.

Typical Details For Cable Tray Installation And Support System

Below drawing shows how to install cable tray and its support system. This cable tray support system drawing has Isometric view and cross-sectional view. Following are the steps to be done for laying cables on wall mounted cable tray:

  1. Install cable tray support using a pre-fabricated flange or GI channel. The size, length and intervals of the support to be as per the specification, standards, number of cables, and size of the cable.
  2. Fix the cable tray as shown on the drawing.
  3. Lay the cable keeping the distance as per calculation.
  4. Tie the cable using cable tie and label the cables as required.

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.

Public Address System In Electrical Construction Contract

The contractor shall supply, installation, test and commission a public address system consisting of power amplifier, mixer power amplifier, microphone module, paging console, cabinet rack, conduits and wiring and all the necessary equipment required by the system shown and described on drawings, bill of quantities and hereinafter.

Temporary Utilities of Water, Electricity, A/C, Lighting For Construction Site

It will be the Developers responsibility to obtain all necessary approvals from Authorities having jurisdiction for temporary connections to existing infrastructure. Temporary utilities shall be installed in such a manner as not to interfere with permanent construction. The Plot Developer shall provide any temporary holes or sleeves required to install the temporary utilities and shall be responsible to fill the same upon removal of utilities.