Laboratory 2

Abstract

The experiment was perfomed to understand the used of two devices which are the
oscilloscope and the function of generator. The oscilloscope is an instrument that used to
display and analyze the waveform of electronic signals. In effect, the device draws a graph of
instantaneous signal voltage as a function of time. Furthermore, the first is the peak-to-peak
voltage (Vpp), which is defined as the voltage difference between the time varying signal’s
highest and lowest voltage. the second is the frequency of the time-varying signal (f), defined
by f = 1/T, where f is the frequency in hertz (Hz) and T is the period in seconds (s). We used the
digital oscilloscope for this experiment. Based on the results, for the activity 1, the volt/DIV was
2.The amplitude for activity 2 was 4V and the period was 1000µs and the frequency was
0.004µs. For activity 3, the amplitude was 4V and the period was 1000µs and the frequency was
0.01µs.

Introduction (purpose and theory)

This report introduced to the students about the operation of each control on an digital
oscilloscope. Besides, students can know how to measure unknown electrical signal on digital
oscilloscope. The oscilloscope is used to observe the shape of the signal and measure the
voltage at different times. If the signal is periodic we can also measure the frequency, the rate
of repeating, of the signal. An oscilloscope contains a cathode ray tube (CRT), in which the
deflection of an electron beam that falls onto a phosphor screen is directly proportional to the
voltage applied across a pair of parallel deflection plates. A measurement of this deflection
yields a measurement of the applied voltage. The oscilloscope can be used to display and
measure rapidly varying electrical phenomena. Moreover, there are two types of voltages
which are AC and DC. The beam is deflected along the way by vertical and horizontal plates that
use electric fields to deflect the electrons.
Apparatus

1. Digital oscilloscope
2. Oscilloscope probe
3. DC power supply
4. Function generator

Procedure

Activity 1

1. The oscilloscope probe is attached to the output probe of a DC power supply.

Activity 2

1. The oscilloscope probe is attached to the signal probe of the function generator.
2. The output signal of the function generator is set to a sinusoidal at 4 Vpp and 200 Hz.
3. The amplitude and the frequency of the sinusoidal signal is drew and measured. The
appropriate control settings of the oscilloscope that have chosen is written.

Activity 3

1. The oscilloscope probe is attached to the signal probe of a function generator.

Activity 1

Volt/DIV : 2V/DIV
Activity 2

Volt/DIV : 2V/DIV

Time/DIV : 250 µs

Amplitude : 2 × 2 V

=4V

Period : 4 × 250 µs

= 1000µs

Frequency : 1/250

= 0.004 µs

Activity 3
Volt/DIV : 500mV/DIV

Time/DIV : 100µs

Amplitude : 8 x 500mv

= 4000 mV = 4V

Period : 10 x 100 µs

= 1000 µs

Frequency : 1/100 µs

= 0.01 µs

Conclusion
As a conclusion, we have completed the purpose of the experiment to measure the unknown
electrical signal on the digital oscilloscope. Through the experiment, we can know shape of the
signal, voltage, amplitude, period and the frequency. Furthermore, we are able to handle the
digital oscilloscope, DC power supply and the function generator. Digital oscilloscope is better
than voltmeter and multimeter because it can show the waveshape of the signal.

References

How to use oscilloscope, [website] retrieved from

https://learn.sparkfun.com/tutorials/how-to-use-an-oscilloscope

Things you need to know about digital oscilloscope , [website] retrieved from

https://www.rdmag.com/article/2015/05/things-you-need-know-about-digital-oscilloscopes
LABEL FUNCTION
1. Power on/off button
2. Power Indicator which lights when the oscilloscope is on. This may be an LED in
newer scopes or a neon tube in older scopes.
3. The trace rotation (TR) control. This sets the inclination of aflat signal relative to
the graticule. This is usually a Trimpot and needs to be set using a flat-bladed
screwdriver. Once set, this control should retain its position and will rarely need
adjusting.
4. The intensity of the trace. Turning this up increases the brightness of the trace
and turning it down makes it dimmer. An overly bright trace can damage the
phosphor of the screen if the dot is moving too slowly. The trace can get fuzzy if
the electron beam is not focused correctly.
5. The focus control set this. Most scopes can focus the beam to form a trace
about 1mm wide.
6. The calibration point. Tis gives a steady square wave at a set frequency and
voltage, allowing the scaling of the trace to be set accurately. Sometimes, more
than one frequency and voltage is available to give a more representative
calibration. The standard calibration signal is between 0V and 2V at 1kHz.
7. Controls the position of the trace. It can be adjusted to set the voltage relative
to a ground or it can be adjusted to separate the two signals – perhaps the first
 channel in the top half of the screen and the second channel in the bottom.
8. Inverts the relevant channel. That is, the negative voltage is displayed and the
trace is upside-down.
9. The vertical scale control, often called the volts/div. Control. This sets the
height of the trace. It operates in discrete steps.
10. Variable height control. It can adjust the height of the trace up to the next set
increment on the volts/div. control. When set to cal, the height is as stated on
the volts/div. Control.
11. The AC/DC toggle. When set to AC, any DC component of the voltage is filtered
out by switching a capacitor in series with the input signal, leaving just an AC
voltage. this is useful when
12. The GND toggle. By selecting this, the input signal is ignored, and the trace
shows 0V. this can be useful to measure a voltage or to eliminate one of the
traces from the display.
13. The Channel 1 signal input.
14. Is the Channel 2 input. This is where the oscilloscope’s probe is plugged in. Each
channel has a copy of most of these controls (except chop/alt, which applies to
all channels.)
15. Which is usually a sliding switch. When set to channel 1, only the trace from
channel 1 is displayed and likewise for channel 2. When dual is selected, the
traces are shown side by side. This is when the chop/alt control applies. Add
shows the sum of the two traces as on trace. By inverting the traces, one can be
substracted from the other. This can be seen in the illustration below. This
shows a square wave on one channel and a sinusoidal wave on the other. On
the left, the scope is set to “dual” , and the two traces are shown side by side.
On the right, the scope is set to “add” , and the trace is the sum of the two
signals.
16. Is a very useful control if you want to quickly zoom in on a feature without
changing the time base and using your setting. This button magnifies the
 central area of the trace by a factor of 10 in the horizontal direction (but leaves
the voltage height unchanged)
17. This is useful if part of the trace is off the edge of the screen but you do not
want to change the timebase.
18. Toogles the mode between the usual voltage vs time format and the xy mode.
This continuously plot the voltage on channel 1 along the horizontal axis against
the voltage on channel 2( the vertical axis). This can be extremely useful to
analyse frequency or phase relationship. This is a complex topic, and will be
covered in it own section later in the module.
19. The time base is the length of time displayed per major horizontal division on
the screen. This ranges from about 0.1 miliseconds to about 1 second (or more
on digital scopes). The position of the trace from side to side is controlled by
17.