PASCO WA-9613 Driver_Detector Coils - Manual (Page 3)

3
012-03479C Driver/Detector Coils
To connect the Driver/Detector Coils to a Power
Amplifier and PASCO Computer Interface:
• Connect the Power Amplifier DIN plug to channel
C of the interface. Connect the Driver Coil to the
output of the Power Amplifier.
➤ CAUTION: Do not turn on the power amplifier
until you have set the output amplitude from within
the program.
For the Series 6500 Computer Interface (e.g., CI-
6500):
• Connect the BNC plug on the Detector Coil to the
BNC jack on the CI-6508 Input Adapter Box, and
the DIN plug on the Adapter Box to channel A of
the interface. Turn the amplification select switch
on the CI-6508 to 100X.
For the CI-6550 or CI-6565 Computer Interface
• Connect the BNC plug on the Detector Coil to the
BNC adapter that is included with the Driver/De-
tector Coils. Connect the banana plugs of a CI-
6503 Voltage Sensor to the BNC adapter. Connect
the DIN plug of the Voltage Sensor to channel A
of the interface.
To connect the Driver/Detector Coils to a Function
Generator and PASCO Computer Interface:
• Connect the Driver Coil to the output of the func-
tion generator
For the Series 6500 Computer Interface (e.g., CI-
6500):
• Connect the BNC plug on the Detector Coil to the
BNC jack on the CI-6508 Input Adapter Box, and
the DIN plug on the Adapter Box to channel A of
the interface. Turn the amplification select switch
on the CI-6508 to 100X.
For the CI-6550 or CI-6565 Computer Interface
• Connect the BNC plug on the Detector Coil to the
BNC adapter that is included with the Driver/De-
tector Coils. Connect the banana plugs of a CI-
6503 Voltage Sensor to the BNC adapter. Connect
the DIN plug of the Voltage Sensor to channel A
of the interface.
If you have another CI-6503 Voltage Sensor, use it to link
the function generator to channel B of the interface. (This
step is optional; it allows you to use the function genera-
tor for triggering, with slightly improved results.)
➤ NOTES
➀
For resonant wave patterns with an antinode in
the center of the string (symmetrical patterns), you
may occasionally see higher or lower harmonics
superimposed on the driving frequency.
➁
If the driver and detector coils are too close to-
gether, the mutual inductance of the two coils may
be great enough to induce a signal in the detector
directly. The distance between the coils that is re-
quired to avoid this mutual inductance depends on
the amplitude of the signal from the function gen-
erator to the driver coil, so you may need to experi-
ment a bit to be sure your signal is coming only
from the vibrating wire.
➂ However, even if the signal to the detector is
affected by mutual inductance, it should still be
possible to locate the nodes and antinodes of a
standing wave pattern. As you move the detector
coil along the string nearer to the driver coil, the
signal due to mutual inductance will rise steadily
with decreasing distance. The nodes and antinodes
of the wave pattern should still be detectable as
relative maxima and minima within this steadily
rising amplitude.