1. In the name of Allah, Who is Omnipotent, Omnipresent
2. Group No 1
Engr. Sadia Tabbassum
Shahid Ali (sp12-epe-031)
Fida Ali (sp12-epe-021)
Dilawar Hussain (sp12-epe-046)
Mazahir Hussain (sp12-epe-062)
What is an oscilloscope?
what can you do with it?
How does it work ?(THROUGH
This section answers these fundamental
4. What is an oscilloscope?
Introduced by German Physicist Ferdinand Braun in
"The oscilloscope is basically a graph-
displaying device - it draws a graph of an
Electrical Signal Visual signal
-ALSO CALLED electron beam voltmeter.
5. This simple graph can tell
you many things about a
signal. Here are a few:
• You can determine the time and voltage values of aYou can determine the time and voltage values of a
• You can calculate the frequency of an oscillating signal.You can calculate the frequency of an oscillating signal.
• You can see the "moving parts" of a circuit representedYou can see the "moving parts" of a circuit represented
by the signal.by the signal.
• You can tell if a malfunctioning component is distortingYou can tell if a malfunctioning component is distorting
the signal.the signal.
• You can find out how much of a signal is direct currentYou can find out how much of a signal is direct current
(DC) or alternating current (AC).(DC) or alternating current (AC).
• You can tell how much of the signal is noise and whetherYou can tell how much of the signal is noise and whether
the noise is changing with time.the noise is changing with time.
6. What Can You Do With
• Oscilloscopes are used by everyone.
• Television repair technicians.Television repair technicians.
• An automotive engineer uses anAn automotive engineer uses an
oscilloscope to measure engineoscilloscope to measure engine
• A medical researcher uses an oscilloscopeA medical researcher uses an oscilloscope
to measure brain waves.to measure brain waves.
The possibilities are endless.
"An"An analoganalog oscilloscope works by directly applyingoscilloscope works by directly applying
a voltage being measured to an electron beama voltage being measured to an electron beam
moving across the oscilloscope screen."moving across the oscilloscope screen."
"In contrast, a"In contrast, a digitaldigital oscilloscope samples theoscilloscope samples the
waveform and uses an analog-to-digitalwaveform and uses an analog-to-digital
converter (or ADC) to convert the voltage beingconverter (or ADC) to convert the voltage being
measured into digital information."measured into digital information."
10. Major blocks in Block DiagramMajor blocks in Block Diagram
earlier are,earlier are,
• 1. CRT
• 2. Vertical amplifier
• 3. Delay line
• 4. Time base
• 5. Horizontal amplifier
• 6. Trigger circuit
• 7. Power supply
Let's get familiar to the above
• CRT stands for Cathode Ray Tube.
Cathode Ray Tube is the heart of the
oscilloscope. When the electrons emitted by
the electron gun strikes the phosphorus screen
of the CRT, a visual signal is displayed on the
13. 2. Vertical Amplifier
• In Vertical Amplifier,The input signals are
amplified by the vertical amplifier. Usually,
the vertical amplifier is a wide band amplifier
which passes the entire band of frequencies.
15. 3. Delay Line
• Delay Line as the name suggests that, this
circuit is used to, delay the signal for a period
of time in the vertical section of CRT. The
input signal is not applied directly to the
vertical plates because the part of the signal
gets lost, when the delay Time not used.
Therefore, the input signal is delayed
by a period of time.
16. 4. Time Base Circuit
• Time base circuit uses a uni junction transistor,
which is used to produce the sweep. The saw
tooth voltage produced by the time base circuit
is required to deflect the beam in the
horizontal section. The spot is deflected by the
saw tooth voltage at a constant time dependent
17. 5. Horizontal Amplifier
• In Horizontal Amplifier, The saw tooth voltage
produce by the time base circuit is amplified
by the horizontal amplifier before it is applied
to horizontal deflection plates.
18. 6. Trigger Circuit
• Well when an signal is applied to the input of
the CRO we require a mechanism that tells the
CRO to trace the input signal on the display.
This mechanism is called the CRO Triggering
19. 7. Power supply
• The Power supply voltages require by CRT,
horizontal amplifier and vertical amplifier are
provided by the power supply block.
20. Power supply block of
oscilloscope is classified in to two
• (1) Negative high voltage supply
• (2) Positive low voltage supply
• The voltages of negative high voltage supply is from
-1000V to -1500V and the range of positive voltage
supply is from 300V to 400V approx.
• As picture Tube in TV
• Radar System to detect enemy aircraft.
• To measure voltage or current, the drop
across a resistor is measured.
• To study waveforms: A visual display is
• Measurement of frequency and phase