PASCO WA-9612 RESONANCE TUBE - Manual (Page 6)

Resonance Tube 012-03541E
2
1 2 3 4 5
SPEAKER INPUT
.1 W MAX
ON
OFF
ON
OFF
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WA-9612
RESONANCE TUBE
13 13
You will also need:
• A function generator capable of driving the 32
Ω
,
0.1 W speaker (such as the PASCO PI-9587B
Digital Function Generator.
• An oscilloscope (such as the PASCO SB-9591)
• Banana plug hook-up wires for connecting your
function generator to the speaker
To set up the Resonance Tube
(see Figure 2):
➀ Set up the equipment as shown in Figure 2. The mi-
crophone can be mounted in the microphone hole
below the speaker, or, as shown in the lower insert,
it can be taped to the end of the microphone probe
rod and inserted through the mounting hole so that
nodes and antinodes can be located within the tube.
You can also vary the effective tube length by in-
serting the moveable piston as shown in the upper
insert. The end of the piston rod that is outside the
tube should be supported to avoid putting excessive
strain on the piston.
➁ Set the frequency of the function generator to ap-
proximately 100 Hz, and the amplitude to zero,
then turn it on. Slowly raise the amplitude until you
hear a sound from the speaker.
➤ CAUTION: You can damage the speaker by
overdriving it. Raise the amplitude cautiously.
The sound from the speaker should be clearly
audible, but not loud. Note also that many
function generators become more efficient at
higher frequencies, so you may need to reduce
the amplitude as you raise the frequency.
➂ Turn on the oscilloscope and switch on the battery
powered amplifier. Set the sweep speed to approxi-
mately match the frequency of the signal generator
and set the gain until you can clearly see the signal
from the microphone. If you can’t see the micro-
phone signal, even at maximum gain, adjust the fre-
quency of the signal generator until the sound from
the speaker is a maximum. Then raise the ampli-
tude of the signal generator until you can see the
signal clearly on the oscilloscope.
➃ You can now find resonant modes by adjusting the
frequency of the sound waves or the length of the
tube, and listening for a maximum sound and/or
watching for a maximum signal on the oscilloscope.
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WA-9612 RESONANCE TUBE
13 13
SPEAKER INPUT
.1 W MAX
BK PRECISION 200 Mhz OSCILLISCOPE
MODEL 2120
INTENSITY FOCUS
TRACE NOTATION
TRIG LEVEL
COUPLE SOURCE
SLOPE λ - Y
TIME/DIV
X-POS
VAR VAR
VAR SWEEP
CAL CAL mV V
CH 1 VOLTZ/DIV CH 2 VOLTZ/DIV
CAL mV V
VERTICAL MODE
PULL XS PULL XS
CH 2
∞
CH 1 ∞
AC
DC
AC
DC
AC CH1
CH2
ALT
EXT
POS POS NORM
EXT CH1
CH2 NORM
EXT CH1
CH2
MANUAL AUTO
T X-Y
T X-Y
LINE
CAL EXT CH4
POWER 200V MAX 400V MAX 400V MAX
- + +
-
T T L
H I Ω
G N D
L O Ω
M I N
R A N G E
A D J U S T
M A X
O U T P U T F R E Q U E N C Y
A M P L I T U D E
P I - 9 5 8 7 B
D I G I T
A L F U N C T I O N
G E N E R A T O R - A M P L I F I E R
H E RT Z
W AV E F O R M
I N P U T G N D
E X T E R N A L
ON
OFF
ON
OFF
Oscilloscope
Using the moveable piston to vary the
tube length
Using the microphone probe rod
Function generator
Figure 2 Equipment Setup