PASCO ME-8750 HARMONIC OSCILLATOR_DRIVER - Manual (Page 2)

2
Harmonic Oscillator/Driver 012-05931A
®
➁ Amplitude Adjustment: To vary the amplitude,
loosen the thumb screw that holds the arm to the mo-
tor shaft and slide the arm to a new position. Re-
tighten the thumb screw to hold the arm in place. The
amplitude is zero when the arm is positioned such that
the screw which holds the string holder is aligned over
the motor shaft.
➂ Power Supply: Plug the leads from the Oscillator/
Driver into a 12 V (0-0.3 A) variable DC power supply.
➤ NOTE: Do not exceed 12 V.
➃
Frequency Adjustment: To adjust the frequency,
change the voltage of the power supply. An increase
in the voltage corresponds to an increase in the fre-
quency.
➄
Measuring the Frequency: Mount a photogate onto
the Oscillator/Driver using the slot located below the
motor. Each period, the arm will block the photogate.
See Figure 1.
Suggested Uses for the Oscillator/Driver
➀
Attach a spring to each end of a dynamics cart. Con-
nect the free end of one spring to the adjustable end
stop at one end of the dynamics track. Connect the
free end of the second spring to a string tied to the
Oscillator/Driver and threaded through the string
guide. Drive the spring and cart system at various fre-
quencies to find the resonant frequency of the system.
➤ NOTE: It generally takes the system a little
time to respond to a change in frequency of the
driving force so some patience is needed to see the
resulting change in amplitude.
➁
Use two carts and three springs to find the resonant
frequencies of the two different modes of oscillation.
See Figure 3.
Other Suggested Uses Requiring Additional
Push/Pull Accessory
➂
Mount the Oscillator/Driver on a rod stand and hang a
Longitudinal Wave Spring (WA-9401) from the hook
on the Push/Pull accessory. Create a transverse wave
in the spring to demonstrate that the wavelength varies
down the length of the hanging spring.
➃
Drive a set of hanging balls (see Figure 4) at various
frequencies to show different modes of oscillation and
chaotic motion.
Dynamics Track
Harmonic
Oscillator/Driver
Springs
Dynamics Carts
Adjustable
End Stop
Figure 3: Resonant Modes of Oscillation of Carts and Springs