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ELECTRIC CIRCUITS

Electric circuit can be defined as the path provided for easy flow of electric current.  It is for conversion of the electric current into useful purposes such as lighting and heating.  Electric circuit is connected or fitted with devices that control and measure the current and energy used in the process.

Simple electric circuit

 

BASIC COMPONENTS OF ELECTRIC CIRCUIT

THE CELL OR BATTERY

The cell or battery is to push the free electrons round the circuit.  The work done when one coulomb of charge moves from one point to the other in the conductor is known as potential difference (p.d).  It is measured in volt.  The instrument used for measuring the potential difference is called the voltmeter (v).The ammeter (A) is used to measure the current flow.  Current is represented by the symbol I and it is measured in Amperes.  The instrument used for measuring current is called the ammeter.

 

RESISTANCE AND E.M.F

RESISTOR: This is a component that opposes the free flow of electrons in the circuit.  Resistance (R) is measured in Ohms (Ώ) using Ohmmeter.

E.M.F (Electromotive force):   this is the force that moves the electrons in the circuit.  It is represented with V and measured in voltage using a voltmeter.  It is the force that moves the current round electric circuit

See also  BASIC ELECTRICITY

 

SOURCES OF E.M.F

  1. Dry cell or primary cell (1.5V each)
  2. Wet cell or secondary cell (12V each)

 

ARRANGEMENT OF ELECTRIC CIRCUIT

Electric circuits can be arranged in the following ways

  • Series arrangement (ii) parallel arrangement (iii) combination of series and parallel arrangement
  • Series Arrangement

Parallel Arrangement

 

EVALUATION QUESTION

  1. (a) Define an electric circuit (b) draw a simple electric circuit
  2. State the instrument used in measuring (i) potential difference (ii) current
  3. Define: (a) potential difference (b) E.M.F (c) state two source of E.M.F

 

GENERAL EVALUATION

  1. Mention 5 workshop safety devices
  2. Mention 5 drawing instruments and materials

 

WEEKEND ASSIGMENT

  1. The instrument used in measuring the potential difference across the conductor is …… (a) ohmmeter (b) voltmeter (c )ammeter (d) waltmeter
  2. Resistance is measured in (a) ampere (b) volt (c) ohms (d) watt
  3. We can measure resistance using ———– (a) ammeter (b) ohmmeter (c) voltmeter
  4. Which of the following is not possible in the arrangement of the electric circuit? (a) series (b) parallel   (c) buttress    (d) combination of series and parallel.
  1. Which of the following is not a basic component of electric circuit (a) resistance (b) cell (c) current (d) capacitor
See also  Sound Energy

 

THEORY

  1. State the unit of measurement and the instrument used in measuring the following (a) resistance (b) electric current (c) potential difference
  2. How would you take care of file

 

See also

MAINTENANCE

HOLDING DEVICES

HAND TOOL

METAL WORK

WOODWORK HAND TOOLS

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