Sunday, 4 December 2011


An oscilloscope is a measurement and testing instrument thet measures AC waveforms with two-axis on screen :

1. Vertical Axis

Represent the voltage.

2. Horizontal Axis

Represent the time or phase angle.

The quantities can be shown on the screen of an oscilloscope :

1. Amplitude ( Peak value, Vp).
2. Peak-to-peak value (Vpp).
3. Period (T) and frequency (f).

Example :

From figure as shown below, shows a AC sine wave displayed on the screen of an oscilloscope. The voltage knob is set at 5 v/div. Calculate the Peak-to-peak value (Vpp).

Solution :

The variable value (v/div) = 5v/div
The number of vertical division = 6.4 division.

Therefore, peak-to peak value (Vpp) :

= 5v/div X 6.4div
= 32V

Vp = Vpp/2 

Introduction of Electricity

The Importance And Need For Electricity In Daily Life.

All electrical appliances need electricity in order to function.

Example of electrical appliances :

a) heat energy.

b) sound energy.

c) light energy.

d) mechanical energy.

Electrical Energy Resources :


Heat when applied to the tip of two different metal wires will produce a voltage.


When light is shone onto the surface of selenium, lithium, and semiconductor materials such as silicon, voltage will be generated.


Current is induced when a  conductor is passed thought a magnetic field.


Different strength of pressure exerted on a crystal will generate voltage.


A chemical reaction between zinc and copper in electrolyte will produce electric charge as in a battery cell.


Friction between two differenr materials will produce electrostatic force.