Physics Laboratory 2
last update: 2009. 8. 31
Reference
- How to Use an Oscilloscope -
Purpose of Experiment
Oscilloscope shows voltage signal in eyesight and essential device in physics
experiment.
1. Front panel
(1) Power switch on/off
Check the LINE voltage and put a power OFF, put a plug to the AC INLET
Power switch is PUSH BUTTON SWITCH and pushed state is ON.
(2) POWER LAMP
Light is on(green) when power is ON.
(3) INTENSITY KNOB
It lets you adjust the plotted waveforms to account for various signal characteristics, such
as fast sweep speeds and low trigger rates. Before put power, turn to the ends
counterclockwise direction.
(4) FOCUS KNOB
Controlling INTEN it lets you adjust the waveforms. Controlling INTEN focus automatic.
When focus is distorted, adjust again.
(5) TRACE ROTATION VOLUME
It calibrates a distortion of horizontal line due to earth magnetic field.
(6) SCALE ILLIM KNOB
It controls an amplitude of light in Brown plane. It gets lighter rotating clockwise. It is
used as measuring in dark place or taking photo.
(37) FUSE HOLDER
It chooses the power getting to the oscilloscope
(39) AC INLET
It is power CORD CONNECTOR.
1. Vertical axis
(30) CH1 INPUT CONNECTOR
It is vertical input BNC CONNECTOR. Signal in this channel is x-axis signal when used X-Y
OSCILLOSCOPE
(24) CH2 INPUT CONNECTOR
It is same as CH1. But Signal in this channel is y-axis signal when used X-Y OSCILLOSCOPE
(22)&(29) AC-GND-DC SWITCH
It choose connecting method between input signal and vertical amplifier
AC : connected by condenser. DC component of input signal is cut off, only AC component is
indicated
GND : Input of vertical amplifier is grounded.
DC : It connects directly. Input signal includes DC.
(25)&(33) VOLTS/DIV change switch
It is STEP attenuator change vertical axis deflection sensitivity. It is set to measure easily vary
with size of input signal.
(Caution : Convert 10 times if you use with 10:1 probe)
(26)&(32) VAR KNOB
It is minuteness KNOB changing vertical axis deflection sensitivity . It is attenuated less than
1/2.5 when fully rotated in reverse of an arrow. It is used as measuring two phenomena,
comparing waveform. In general it is rotated fully in arrow.
(20)&(36) PUSH S/W ‘5 MAG GAIN KNOB
When it is pushed gain of vertical axis is magnified 5 and max sensitivity becomes 1mV/div
(23)&(35) POSITION
It moves bright line up and down
(21) PUSH S/W INVERT KNOB
Function of POSITION is same as POSITION 35 in CH1. If it is used pushing KNOB in 21,
polarity of input signal in CH2 is reversed. It is used as comparing 2 waveforms having
different polarity, measuring a waveforms of phase difference of CH1 and CH2 using ADD.
In general KNOB is pulled out.
MODE conversion KNOB
It choose method of vertical axis
(34) CH1 : It shows only CH1 signal in front panel.
(28) CH2 : It chows only CH2 signal in front panel.
(34)&(28) DUAL : Each vertical amplifier in CH1 and CH2 is converted into CHOP and ALT. It
becomes 2channel oscilloscope. It is used as measuring 2 channel waveforms when sweep
time is late.
(31) ADD : Adding or subtracting of input signal in CH1 and CH2 is showed in front panel.
(40) CH1 OUTPUT CONNECTOR
It is signal output terminal as frequency counter. It generates input signal of CH1 as
amplitude of 20mV/div(using 50 Ohm)
2. Horizontal axis.
TIME/DIV conversion switch
(15) SWEEP TIME : It can converted as 0.1 microS/div~0.2S/div
(11) X-Y : It is used when using X-Y oscilloscope
Input X, Y signal into CH1 and CH2 respectively. Read vertical axis bias sensitivity as CH2
Volts/Div, horizontal axis bias sensitivity as CH1 Volts/’Div. Control vertical position as CH2
Position 23, horizontal position as H-Position 14.
(12) SWEEP VAR KNOB
Rotating fully as an arrow direction it is revised as Time/Div being CAL. Rotating fully as an
reverse arrow direction SWEEP is late less than 1/2.5. In general it is rotated as CAL.
(14) POSITION KNOB
Bright line is moved as rotating direction.
(9) PUSH’5 MAG(PUSH ‘10MAG(
It moves line horizontally. It magnifies SWEEP 5(10) times pushing ‘5MAG(‘10MAG)KNOB.
SWEEP TIME/DIV becomes 1/10(1/5) times of data.
(8)ALT MAG KNOB
It converts SWEEP of input signal from CH1, CH2 sweeping ‘1(NORM) and
‘5MAG(‘10MAG). We can measure waveform of ‘1 and ‘5(10) waveforms
simultaneously.
3. (18) SOURCE convert SWITCH
It chooses SWEEP signal source.
INT : Input signal induced at CH1 or CH2 becomes signal source.
CH2 : Input signal induced at CH2 becomes signal source.
LINE : power frequency becomes signal source.
EXT : External signal induced at TRIG becomes signal source. It is used as using other signal
different with vertical axis signal.
(19) EXT INPUT CONNECTOR
Input signal of SWEEP.
(17) TRIG LEVEL KNOB
It sets TRIG LEVEL and determines location of SWEEP in waveform. KNOB 10 converts SLOPE.
(16) TRIG MODE conversion SWITCH
AUTO : It SWEEP continuously. When signal is in wave form isn’t move but signal is off bright
line is occur.
NORM : It SWEEPs only same period is in. If there is no signal there is no bright line.
TV-H : It is used only set TRIG MODE as TV.
TV-V : It is valid only set TRIG MODE as TV and used as measuring vertical signal of TV
signal.
(39) Z-AXIS INPUT CONNECTOR
Input terminal for modulation.
(7) CAL 0.5V terminal
Output terminal of revision of wave as 1KHz, 0.5V.
(27) GND terminal
Grounding terminal
4. Showing bright line
Check input voltage between put the POWER SWITCH. If converter is set as AC
100V, check the input voltage being 90~110V. Choosing input source refer the sign
of back panel. Put the Cord into AC INLET and set each KNOB ;
POWER
OFF
INTENSITY
fully rotate into counterclockwise direction
FOCUS
center
AC-GND-DC
GND
D POSITION
center (5 5MAX KNOB is OFF)
N POSITION MODE
CH1
TRIG MODE
AUTO
TRIG SOURCE
INT
TRIG LEVEL
center
TIME/DIV
0.5ms/div
POSITION
center
Put the POWER SWITCH on after setting. Bright line is occurred after rotate INTEN
KNOB into clockwise direction. Before measure, rotate FOCUS KNOB and make
bright line clear. When don’t measure, rotate INTEN left and lower brightness.
5. General measuring
(1) Measure 1 waveform
Using CH1 or CH2 except when measuring 2 waveform simultaneously or using X-Y
oscilloscope. Setting using CH1 is given by;
MODE SWITCH in vertical axis ------------ CH1
TRIG MODE SWITCH --------------------- AUTO
TRIG SOURCE SWITCH ------------------ INT
Repeat signal of 25Hz exerted in CH1 can be measured. Measuring less than 25Hz, we
need to convert.
TRIG MODE SWITCH --------------------- NORM
Vertical MODE SWITCH ---------------- CH2
TRIG SOURCE SWITCH --------------- CH2
(2) Measure 2 waveform
Set vertical MODE SWITCH as DUAL. If you change TIME/DIV Range it is set ALT, CHOP.
Measuring phase difference, measure as former phase signal.
(3) Measure X-Y
Pushing X-Y switch, it moves as X-Y oscilloscope.
X-axis signal ------------------- CH1 INPUT
Y-axis signal ------------------- CH2 INPUT
5, 10 MAG switch in horizontal axis should be pulled.
(4) Using ADD
Setting ADD in vertical axis MODE switch, we can measure add of 2 waveform.
6. Connecting signal
Input the signal into oscilloscope is first step of measurement.
Using PROBE
: Using additional probe to measure high-frequency signal. In this case input signal is
attenuated as 1/10 so it is for big signal, not small signal.
7. Measuring
Take the brightness and FOCUS into best place and make easy to read.
Show wave form as big to make error from eyesight small.
-
-
Measure DC voltage
Set AC-GND-DC switch into GND. Set sufficiently Volt/DIV and AC-GND-DC as DC. Bright
line is moved as DC signal, so checking difference between VOLTS/DIV and moving line
we can get DC voltage. In above picture, if VOLTS/DIV is 50mV/div, 50mV/div 5 4.2 =
210mV
-
Measure AC voltage
It is same as DC voltage. In above pic, when VOLTS/div is 1V/div, 1V/div5 5=5V
p-p.
-Measure Frequency, amplitude
In above pic, 1 period is from A to B, and 2.0div. Assuming time is 1ms/div, period is
1ms/div5 2.0=2.0ms. So frequency is 1/2.0ms=500Hz.
-
Measuring time difference
Measuring time difference of 2 signal, set a same period signal as reference signal. If
there is signal as pic (a), same period signal is shown (b) when CH1, shown as (c) when
CH2. So checking lateness of CH2 relative of CH1, set a same period signal as CH1, or
CH2 vice versa.
Outline of Experiment

Observe origination, propagation and velocity of electromagnetic wave.

Using laser pointer as light source, observe reflection, refraction and polarization
of light.
- How do you experiment?
- What measure?
Experimental Method
These equipments are prepared in the laboratory. (Parentheses mean the number of
References

Constant current(voltage) power supply

Measurement of specific heat of an object - calorimeter

Measurement of temperature by the thermocouple and the digital thermometer

Treatment of measurement data

Analysis method based on the graph

James Joule - The importance of precise measurement
Return to Index