TERMINATING AND CONNECTING ELECTRICAL WIRING AND ELECTRONICS CIRCUIT (TCEW)

Electric circuit is a path for transmitting electric current. It includes a tool that provides energy to the charged particles constituting this, like battery or a generator; devices that use current like lamps, electric motors, or computers; and the connecting wires or transmission lines.

 What is It

Unlocking of Technical Terms

• Wire termination is the point where a line, channel or circuit ends.

• Electronic Circuit is a complete course of conductors through which current can travel. Circuits provide a path for current to flow. 

• Electrical wiring is an electrical installation of cabling and associated devices like switches, distribution boards, sockets and light fittings in an exceedingly structure.

• Direct Current (DC) is an electrical charge (current) only flows in one direction. 

• Alternating Current (AC) changes direction periodically. The voltage in AC circuits also periodically reverses because the current changes direction.

• Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system.

• Schematic Symbol is a pictogram used to represent various electrical and electronic devices or functions, such as wires, batteries, resistors, and transistors, in a schematic diagram of an electrical or electronic circuit.

• Voltage is the measure of the push on each electron which makes the electron move. The term potential difference and voltage are often used interchangeably to mean the “push”, thus, you may see the term electromotive force (EMF) or just the word potential to describe the electron push in certain instances. 

• Soldering is a process in which two or more items are joined together by melting and putting a filler metal into the joint. The filler metal has a lower melting point than the adjoining metal. Unlike welding, soldering does not involve melting the work pieces.

• Joint is the connection of two lengths of conductors by a method which ensures a continuous path for the unimpeded flow of an electrical current.

• Termination is applied to the end of a conductor prepared and suitable for connection to the terminal to which is to be connected by mechanical means.

Electrical Theory 

Direct Current and Alternating Current 

1. Direct Current or DC is the first type of current because it was easy to produce. This type of current always flows in one direction. 

2. Alternating Current or AC is the solution to the problem of DC. AC allows the flow of current in two directions. 

Components of a Simple Circuit 

A simple circuit contains the minimum things needed to have a functioning electric circuit. A simple circuit requires the following: 

• AC/DC source  

• Equipment that will operate on either an Alternating Current (AC) or Direct current (DC) power source.  

• Battery is a DC voltage source containing two or more cells that convert chemical energy to electrical energy.  

• Cell is a single unit used to convert chemical energy into a DC electrical voltage. 

• Fuse is a safety device used to protect an electrical circuit from the effect of excessive current. 

• Wires are single electrical conductor that is used to bear mechanical loads or electricity and telecommunication signals. 

• Cable is a group of wires wrapped in one jacket. 

• Switch is a device used to break an electric current or transfer it to another conductor.

• Load is the power consumed by a circuit. Whatever component or piece of equipment is connected to a source and draws current from it is a load.  

The following are examples of loads: 

Bulb, television, refrigerators, computers, mobile phones, and other appliances or gadgets.

Parts of a Simple Circuit 

A simple circuit contains the minimum things needed to have a functioning electric circuit. 

• Source refers to devices used to supply AC or DC voltage. 

• Consuming is any device that consumes voltage, whatever component or piece of equipment that is connected to a source and draws current from a source is a load. 

• Controlling is any device having two states, on (closed) or off (open). 

• Protecting is a component used to open the circuit when current exceeds a predetermined maximum value. 

• Connecting is a material that conducts electric current very well and used to connect a complete path for current. 

Procedures in Circuit Designing 

1. Prepare all the tools and materials needed. 

2. Make a simple circuit by using schematic symbol:  

• load  

• consuming device  

• protecting device  

• connecting device 

3. Make sure that the circuit has the following requirement that a simple circuit must have:  

• a source of electrical potential difference or voltage  

• a conductive path which would allow for the movement of charges  

• an electrical resistance which is loosely defined as any object that uses electricity to do work 

Common Electronic Components

1. Classifications of Electronic Component 

A. Passive devices is one that contributes no power gain (amplification) to a circuit or system. It has no control action and does not require any input other than a signal to perform its function. In other words, "A component with no brains!" Examples are Resistors, Capacitors and Inductors.

B. Active Devices are components that are capable of controlling voltages or currents and can create a switching action in the circuit. In other words, "Devices with smarts!" Examples are Diodes, Transistors and Integrated circuits.

Electronic Schematic Symbols

Electrical & electronic symbols and images are used by engineers in circuit diagrams and schematics to show how a circuits components are connected. The basic electrical and electronic graphical symbols presented here are the more generally accepted graphical symbols because of their common usage across a range of electrical and electronic fields. The individual graphical symbols below are given along with a brief description and explanation.

Use of Tools and Equipment 

To work with electronic and electrical circuits, a beginner must acquire special hand tools and equipment. Each of these hand tools and equipment does one or more specific job in connecting, replacing, securing and troubleshooting of electronic circuits. 

Basic Electronic Hand Tools and Equipment 

A. Common Tools 

• Long Nose Pliers is used for holding, bending and stretching the lead of electronics component or connecting wire. 

• Side Cutter Pliers is used for cutting or trimming of connecting wires or terminal leads within the circuit board. 

• Flat Screwdriver is used to drive or fasten negative slotted screws.

• Philips Screwdriver- is used to drive or fasten positive slotted screws.

• Soldering Pencil is used to join two or more metal conductors with the support of soldering lead melted around it. 

• Desoldering Tool is used to unsoldered unwanted parts or component in the circuit with the support of soldering pencil.

B. Basic Electronic Equipment 

• Multi-Volts Power Supply is an device that supplies electric power to an electrical load. 

• Multimeter is an electronic tool used to measure voltage, amps and resistance across circuits. 

Electrical and Electronic Safety 

Before engaging on any electronics, consider following these basic safety precautions to help reduce any hazards.

1. Remove any electronic equipment you are testing or working on from the ability source. 

2. Never assume the power circuit is off. Test and test again with a voltmeter to confirm. 

3. Remove fuses and replace them only after the power to the circuit is disconnected. 

4. Don’t connect power to a circuit until you are done performing on it and rechecked the work. 

5. Always make sure that all electronics equipment is properly grounded.

 6. If it is damaged, replace it. For example, replace cables instead of repairing with insulating tape. 

7. Always use the proper electronics repair and maintenance tools. 

8. Always return covers after removing them to reduce the chance of electric shock. 

9. Make sure your circuit is not overloaded. 

10. Always have safety equipment such as fire extinguisher, a basic aid kit and a mobile phone nearby. 

11. It is important to make sure that you are safe when working on electronic circuits. 

Safety Procedures in Using Hand Tools and Equipment 

The use of hand tools in accomplishing electronic tasks and jobs are greatly increase the productivity and accuracy of a worker. Although hand tools provide convenience and ease in completing any task, it is also going to cause injuries and infirmities if used incorrectly. Safety procedures should always be a priority in any workplace in order that the security of all is assured. 

Different types of tools can be utilized differently. Listed below are some number of ways to utilize these tools but also maintain safety in using them: 

• Cutting tools like as cutters must be sharpened always. 

• Gripping tools like as pliers must maintain a strong grip. 

• Driving tools like as screw drivers should always be kept straightened. 

• Diagnostic tools like a tester should always be calibrated before use. Use the tools only as recommended by the manufacturer.

Workplace Safety Precautions 

• Workspace must be observed properly. An unsafe workplace can possibly cause harm and injuries. One should bear in mind of the hazards that a piece area is hazardous sometimes. 

• Correct posture must be practiced when using hand tools. Awkward postures make more demands on your body. 

• Use the correct Personal Protective Equipment (PPE) to protect you from exposure to potential hazards. PPEs are specialized gear used to protect the worker from falling objects, loud noises, sharp edges, dust or any particles, and dangerous chemicals. 

• Insulated Gloves prevents electricity from traveling into your hands should there be an exposed wire, short circuit, or other issue. 

• Insulated Matting puts a protective layer between the worker and the floor. It can help prevent electricity from traveling up from the ground into the person’s body. 

• Safety Footwear should be routinely worn in all working areas and also the shoes or boots should incorporate steel toe-cap and non-slip soles. 

• Insulated Ladders prevents transmission of electricity into the person who is using it. 

• Goggles provide protection from impact, dust and chemical splash and provide a secure shield around the entire eye and protect against hazards coming from any direction. 

• Rescue Rods is used to drag someone who is electrocuted within the area for safety or push away the source of electricity. 

• Voltage Detectors shows the level of electricity in a given system at the current time, so employees will not mistakenly begin acting on a system until all power has been eliminated. 

Electrical Cable Jointing Procedures 

From time to time it becomes necessary to splice or join wires together when working with electronic equipment or with electrical wiring. Joining electric power cables is as simple as twisting the wires and taping them. 

Typical Electrical Cable Jointing Methods 

A. Western Union Splice Joint 

This is often a straight joint used for small solid cables.

1. Remove the insulation. 

2. Bring the 2 conductors to a crossed position and then make a long bend or twist in each wire. 

3. Wrap the end of 1 of the wires around the straight portion of the other wire, and then do the same for the other wire. Repeat this for about four or five times. 

4. Press ends of the wires down close to the straight portions of the wire to prevent the ends from piercing through the insulation tape. 

5. Insulate the joint using the electrical tape. 

B. Rattail Joint 

The rattail joint is usually used in the junction boxes to create the joint. 

1. Strip the insulation off the ends of the cable to be joined at about 50 mm. 

2. Twist the wires to create the rattail effect.

C. Fixture Joint 

This is a type of branch joint connecting a small-diameter wire to the large diameter conductor such as those used in lighting fixtures.

1. Remove the insulation. 

2. Wrap the fixture wire around the branch wire. 

3. Bend the branch wire over the completed turns. 

4. Wrap the remaining fixture wire over the bent branch wire. 

5. This can be followed by soldering and taping, or simply taping of the joint.

D. Knotted Tap Joint 

The knotted tap joint is used to branch joints to connect a branch wire to a continuous wire. 

1. Remove about 1 inch of insulation from the main wire and about 3 inches from the branch wire. 

2. Place the branch wire behind the main wire so that three-fourths of its bare wire extends above the main wire. 

3. Bring the branch wire over the main wire, around itself, and finally over the main wire so that it forms a knot. Wrap the wire around the main conductor in short, tight turns and trim its end. 

Typical Electrical Cable Jointing Methods 

Soldering Process

Items to be soldered should normally be "tinned" before making a mechanical connection. Tinning is the coating of the material to be soldered with a light coat of solder. 

Cable Soldering Methods 

There are two types of solder used in electrical work 

1. Fine Solder (tin man’s solder) 

• It has 60% tin and 40% lead 

• Has a low melting point due to high amount of tin 

• Commonly used in electrical joints 

2. Plumbers Metal 

• It has 30% tin and 70% lead. 

• Is used for plumbing joints in armored cables as it remains in a plastic shape allowing it to be shaped longer than fine solder.

Using Analog Multimeter

A multimeter is an instrument used to check for AC or DC voltages, resistance and continuity of electrical components, and small amounts of current in circuits. This instrument will let you check to see if there is voltage present on a circuit. By doing so, a multimeter can help you achieve a variety of useful tasks, such as measuring ohms, volts, and amps.

A. Initial Steps in Using Analog Multi‐tester 

1. Connect the test probe to the appropriate jack. The red test probe to the positive (+) jack and the black to the common (‐) jack.

2. Check if the pointer rests exactly at the infinite zero position in ohmmeter range.

3. Check the probes if they are in condition. 

(Ohmmeter calibration) 

a. Set the Multi‐tester to corresponding selector resistance range. 

b. Short the two test probes lead together.

B. Resistance Measurements 

1. Always do the “Initial Steps in Using Analog Multi‐tester”. 

2. In testing resistors, capacitors, diodes etc. do not touch both test probe lead, because our body also has resistance that could affect the reading value of the electronic components we are testing. 

3. If you do not know the value of the resistor to be measured, find the ohmmeter selector setting until you have a clear reading in the ohmmeter scale.

4. Select the desired resistance range scale with selector switch.

Demands for higher quality and higher production volume have led to many innovations in wire termination. For centuries, copper wire has been used as an electrical conduit. But wire requires termination. Simple screw clamps were originally used to terminate wire. Although screw clamps are still used today, there are now numerous means to terminate wires. 

Proper cable termination practices are vital for the complete and accurate transfer of both analog and digital information signals. A is the work performed to the end of a wire that allows it to connect to a device (connector, switch, terminal, etc.). During termination, you press the cable between two edges of a metal clip, which displaces the insulation and exposes the copper conductor. This ensures a solid connection between the copper conductor and terminating clip.