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.

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.

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.....

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.

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.

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.

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.

Medium Voltage Distribution System In Electrical Construction

The work included within this section is for the supply, connection, testing and commissioning of 13.8 KV switch gears, cables, package sub station and all the related accessories necessary for the proper operation of the system as shown and described on drawings, bill of quantity and herein.

The contractor shall coordinate with the other services (trades) involved in the project to insure that the foundation, are suitable for the equipment to be installed.

Construction Control Guidelines

Construction Control Guidelines of project will help participants to establish right relationship with each other. It explains guidelines and minimum requirements that must be adhered to by developers for the duration of their construction activities. It can be listed as follows:

Electrical Grounding or Earthing Conductors in Building Construction

Buried Earth Conductors:

PVC insulated copper strip conductors or PVC insulated stranded copper cables with cross-section min 70 mm2 or as per earthing calculation.

Earthing Conductors:

PVC insulated copper conductor as described in the Specification for the particular application.

Indoor MV Distribution Panel Boards In Electrical Construction Works

Building projects requires MV Distribution Panel Boards for distribution of power to each utilities. A good electrical distribution network will have proper design, right components, and future load provisions. Space utilization will also be an important factor for maintenance and handling of the equipment. Here we look into what are the features required for design, manufacture, install a MV Distribution panel board including its BIS (IS) standards that serving quality building projects.

Earthing or Grounding Methods for Plant Rooms And Fixed Machinery

Main earthing bar or loop is to be conveniently located in electrical/mechanical plant rooms, and connected by earthing conductors to exposed conductive parts of motor control centre at its earthing bar, and to motors, switches and other electrical equipment etc. at their earthing terminals, using 20 x 2 mm insulated copper strips or 35 mm2 insulated copper conductor (minimum size) or as required to carry maximum earth fault current for 1 second with final conductor temperature not exceeding 200 deg. C (392 deg. F).

Emergency Power Diesel Generating Set In Electrical Construction

This article covers the manufacture, supply, installation, testing and commissioning of 415 volts, 3 ph, 4 wire, Diesel Alternator Set (Diesel Genset). The set shall be mounted on common base frame and complete in all respects including the auxiliary equipment such as battery auxiliary, lube oil pumps, filters, oil storage tank, centrifuge, etc. including piping required for interconnection between the set and the auxiliaries which are mounted separately.

Engineering and Technology

Engineering and Technologies are, in the first instance, simply extensions of the human body, allowing us to overcome the physical limitations with which we are born, and to adapt the natural environment to our own needs. Technologies are inventions of humans that have allowed us to survive, and have enabled our cultures to advance. They are for the most part material objects: tools, for example, are simply detachable additions to the body, the manufacture of which generally distinguishes humans from animals.

Typical Mounting Details Of Fire Alarm Break Glass Manual Call Point

These drawings show how to install Fire Alarm Break Glass (BG) or Manual Call Point (MCP) on walls. It has to be mounted on back box installed in the wall. This box (embedded or exposed as specified in the concerned section of the specification) has to be connected through GI / PVC conduit that will have the Firetuff or equivalent cable to be looped for other detectors. Conduit end to be taken out of the wall above false ceiling to allow the Firetuff cable to be clipped on soffit of the slab.

Drawing below shows how to install Manual call point break glass along with a sounder

In this typical drawing, manual call point break glass unit has been shown as concealed  and the rest  are surface installed in the false ceiling. Sounder has been mounted on ceiling but can also be mounted on wall visibly as per the project specification.

Installation of Audio Intercom System For Building Project

Audio Intercom System being used in high-rise buildings or commercial complexes, provide two way communication from entrances, gates, go-downs, industrial plant rooms and normal doors, to an internal audio handset. It can be used to screen authorized visitors from outside entrance and useful to communicate internally between persons from one room to another room or office spaces. It can also be used to function as effective public announcement system.

Medium Voltage Cables (MV Cables) In Electrical Construction

The contractor shall supply, install, test and commission the 13.8 KV cable network as shown and indicated on the contract documents. Conductor sizes shall be metric as shown, conductor sizes with cross sectional areas smaller than specified will not be accepted. The cable installation shall include all trench work, sleeves, ducts, and all necessary fixings and cable terminations at both ends of the cable. The contractor shall supply and install cable marker posts to indicate the route of all underground cables. Markers shall be provided at every bend along the route and at sites of crossing roads or pipe lines.