Oscilloscope

An oscilloscope is a device used to show waves (or electrical signals) on a screen.

Scale of an oscilloscope

An oscilloscope has two axes:

• The horizontal axis shows time (in seconds, milliseconds, microseconds, etc).
• The vertical axis shows voltage, or potential difference (in volts, millivolts, etc).

The scale of the oscilloscope tells us how much each division (box) on the axis represents.

For example, if the time scale is set to 0.5 ms/div, then each division (box) on the horizontal axis represents 0.5 milliseconds.

If the voltage scale is set to 2 V/div, then each division (box) on the vertical axis represents 2 volts.

Amplitude

The amplitude of a wave can be found from an oscilliscope plot. It’s the distance from the centre line, to the peak (or trough) of a wave (the highest or lowest point).

Period

We can find the period of a wave from an oscilloscope plot. The period is the time taken for one complete cycle of the wave.

To find it, we can measure the distance (in seconds) between two consecutive peaks (or troughs) of the wave.

Frequency

We can calculate the frequency using the formula:

f=\frac1T

Where:

• f is the frequency (in hertz, Hz)
• T is the period (in seconds, s)

For example, if the period of a wave is 0.01 seconds, then the frequency is:

f=\frac1{0.01}=100\text{ Hz}