User manual

PicoScope and oscilloscope primer8

5 PicoScope and oscilloscope primer

This chapter explains the fundamental concepts that you will need to know before

working with the PicoScope software. If you have used an oscilloscope before, then

most of these ideas will be familiar to you. You can skip the Oscilloscope basics

section and go straight to the PicoScope-specific information . If you are new to

oscilloscopes, please take a few minutes to read at least the Oscilloscope basics

and PicoScope basics topics.

5.1

Oscilloscope basics

An oscilloscope is a measuring instrument that displays a graph of voltage against

time. For example, the picture below shows a typical display on an oscilloscope screen

when a varying voltage is connected to one of its input channels.

Oscilloscope displays are always read from left to right. The voltage-time

characteristic of the signal is drawn as a line called the trace. In this example, the

trace is blue and begins at point A. If you look to the left of this point, you will see the

number "0.0" on the voltage axis, which tells you that the voltage is 0.0 V (volts).

If you look below point A, you will see another number "0.0", this time on the time

axis, which tells you that the time is 0.0 ms (milliseconds) at this point.

At point B, 0.25 milliseconds later, the voltage has risen to a positive peak of 0.8

volts. At point C, 0.75 milliseconds after the start, the voltage has dropped to a

negative peak of -0.8 volts. After 1 millisecond, the voltage has risen back to 0.0 volts

and a new cycle is about to begin. This type of signal is called a sine wave, and is one

of a limitless range of signal types that you will encounter.

Most oscilloscopes allow you to adjust the vertical and horizontal scales of the display.

The vertical scale is called the voltage range (in this example at least, although

scales in other units, such as milliamperes, are possible). The horizontal scale is called

the timebase and is measured in units of time - in this example, thousandths of a

second.

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