Asilo, Jairus Rei September 5, 2014Baybay, Ma. Brenda EE 12 V-2LEsteban, Christian PaulFajutagana, Jeffrey RyanMontoya, Daryll

I. Introduction

Oscilloscope is an instrument which provides a graph that displays electrical

signals. This graph represents and measures electric voltages as function of time.

There are two kinds of oscilloscope: analog and digital. In this lab exercise, we used

UNI-T UTD2102CE digital oscilloscope which is labeled oscilloscope # .

Oscilloscopes are important in the laboratories. It is used to observe the wave

shape of a signal, measure the amplitude and frequency of a signal, examine

whether the signal is a direct current (DC) or alternating current (AC), and to

observe noise on a signal.

The main purpose of this experiment is to identify the operating controls of

an oscilloscope, and to set this up and adjust the controls properly to observe an

alternating-current (AC) voltage waveform.

II. Data

Part FunctionPower Button Turns on/off the oscilloscopeChannel 1 / Channel 2 If the probe is connected on CH1, the CH1 button also

turns green. This indicates the channel currently in use. It displays the waveform in the channel where it is connected.

Probe Comp Gives fixed Vp-pand frequencyAutoset Provides a better display of the waveformPosition: Horizontal/Vertical

This moves the wave horizontally or vertically.

Volts/Div Adjusts the voltage value per vertical divisionSec/Div Changes the number of seconds per major division to

display more or fewer cycles.BW Limit Limits the channel bandwidth to reduce the display

noise and high frequency component in the signalDisplay Clicked to change the brightness of the screen.

Turned to the left or right to change the brightness of the screen after clicking the Display button.

Table 1-1. Controls of the oscilloscope and its function

Image 1-1. Probe connected to CH1

Image 1-2. Probe tip attached to the probe comp connector

Image 1-3. General shape of the acquired waveform

Image 1-4. Waveform adjusted to 200 µs using SEC/DIV control

Image 1-5. Waveform adjusted to 500 µs using SEC/DIV control

Image 1-6. Waveform changed from 0.5 V to 2.0 V using VOLT/DIV control

Image 1-7. Image after changing the BW from Close to Open

III. Results and Discussion

We are introduced to the oscilloscope in the lab exercise. We were able to learn how to use this and how to manage the different controls the oscilloscope has in order to adjust the waveform obtained.

As seen in Image 1-1 and Image 1-2, we connected the probe to the oscilloscope in Channel 1 and attached the probe tip to the PROBE COMP connector which has a Vp-p and frequency of 3 V and 1kHz, respectively.

We can see in images 1-3, 1-4, and 1-5 the change in the number of cycles when the DIV/SEC control knob was changed from 100 µs to 200 µs and 500 µs, respectively. This clearly shows the as we increase the value of SEC/DIV, the number of cycles also increase. Therefore, SEC/DIV and the number of cycles have a directly proportional relationship.

Image 1-6 shows the relationship between the height of the waveform and the VOLT/DIV control. As the VOLT/DIV values increases, the height of the waveform decreases. It means that the VOLT/DIV control and the height of the waveform have an inversely proportional relationship.

The trace and appearance of the waveform can be affected by the controls of the oscilloscope. The brightness and sharpness of the trace can be adjusted by clicking the display button and turning the wave bright knob. The location of the waveform can be changed by adjusting the Vertical and Horizontal Knobs.

IV. Conclusion

At the end of the exercise, we are able to setup the oscilloscope. We were

able to identify the basic controls of a digital oscilloscope and to adjust the different

buttons correctly. We learned that there will be no difference when we connected

the probe in channel 1 or channel 2. A green light indicates the channel in use.

Position, either horizontal or vertical, moves the graph to the left and right or up

and down. On the other hand, Volts/Div adjusts the voltage value per vertical

division and is associated with the height of the waveform while Sec/Div changes

the number of seconds per major division to display more or fewer cycles, and

Autoset provides a better display of the waveform when clicked. We understand the

use of each control in order to display a stable display of the signal.