CMA 060 Resonance Kit User’s Guide

CMA 060 Resonance Kit User’s Guide
RESONANCE KIT
Description D060
Figure 1. The resonance kit
CENTRE FOR MICROCOMPUTER APPLICATIONS
http://www.cma-science.nl
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Short description
The resonance kit can be used to introduce some of the basics of oscillation,
resonance, electromagnetic induction, and spring constants to the students.
The kit consists of the following parts:
- Ground plate, including 4 thumb screws
- Long metal bar
- Short metal bar with a mounting hole and thumb screw (attached to the long
metal bar)
- Plastic cylinder, including 1 Philips head screw inserted in the bottom plate
- Coil with a mounting hole and thumb screw
- Magnet holder, with a small screw inserted
- 2x Magnet
- Spring
- Spring holder with two small thumb screws on the sides and one small screw in
the middle
The resonance kit can be used together with a CMA Force Sensor 0663i and a
CMA CoachLab I/II/II+ interface.
The coil can be used as an actuator: by using one of the CoachLab I/II/II+ outputs
to drive current through the coil, the coil can exert a force on the magnets that are
attached to the spring.
The coil can also be used as a sensor: when the magnets that are mounted to the
spring move through the coil, they create a changing magnetic field, and through
electromagnetic induction, a voltage will be induced over the coil that can be
measured directly or through a voltage sensor by the CoachLab interface.
Installation
1. Remove the Philips head screw from the bottom of the cylinder.
2. Mount the cylinder to the ground plate by inserting the Philips head screw
through the hole in the center of the ground plate and inserting it again into the
hole on the bottom of the cylinder.
WARNING: make sure that the adjustable thumb screws at the corners of the
ground plate face down with the plastic part. This is to avoid scratches on the
table or other surface the resonance kit is placed on.
3. Mount the long metal bar to the ground plate by manually turning it into the
hole in the ground plate that is next to the cylinder at the center of the ground
plate. The smaller metal bar should be placed on the top of the long metal bar.
It can be used to hold a force sensor.
4. Mount the magnet holder to the bottom of the spring. For this action, it is
necessary to remove the spring from the cylinder. This can be done by
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loosening the thumb screws at the sides of the spring holder.
5. Depending on the experiment: put the coil around the cylinder and with the
long metal bar inside the mounting hole. Fix it in place by tightening the thumb
screw of the coil.
6. Depending on the experiment: either mount the spring to the spring holder on
top of the cylinder, or mount the spring to a force sensor that is mounted to the
small horizontal bar on top of the long vertical bar.
Suggested experiments
- Determine the spring constant of the included spring. This can be done in
several ways:
- Manually, by attaching known masses to the spring and measuring the
length of the spring.
- Attaching the spring to a force sensor and measuring the force when the
spring is pulled to varying lengths.
- By measuring the period of oscillation when a known mass on the spring
oscillates freely and using T = 2π
m
, with T the period, m the mass and k
k
the spring constant. (In this formula, the mass of the spring and friction are
not taken into account.)
- Study electromagnetic induction, by
measuring the voltage over the coil with
a voltage sensor or directly with a
CoachLab or ULAB interface when a
magnet attached to the spring
periodically moves through the coil.
- Drive the magnet by applying a current
through the coil using one of the output
pairs of the CoachLab I/II/II+.
A small program in Coach can be used
to periodically switch the coil on and off
(or optionally reversing the current). An
example of such a program is:
T=0.8
Repeat
Set(1)
Wait(T/2)
Reset(1)
Wait(T/2)
Until RunningTime > 30
Figure 2. Using a force sensor and
CoachLab II+ with the resonance kit
This program switches the coil on and off when attached to output A with a
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period of 0.8 seconds.
If the period that is used in the program is close to the period of the natural
oscillation of the system, resonance will be clearly visible by a rising
amplitude. If the frequency of the system and the driving frequency differ a
little, this will result in beats.
Tips for using the coil to move the magnet:
- A coil actuator icon must be put on the output pair that is used inside the
Coach application.
- If you leave the program window on the screen the program will be
executed slower (monitor mode), so it is advised to close the program
window when executing the program.
- Shift the coil up or down to find the best position to drive the magnet.
- Play with the power delivered to the coil by adjusting the power slider at the
side of the actuator icon in Coach.
- Try both “pulling” and “pushing” the magnet by reversing the current
through the coil or reversing the magnets.
Technical specifications
Coil
R ≈ 15 Ω, L ≈ 24 mH
Spring
Spring constant: 3 to 4 N/m
Magnet holder
Mass: 16 g
Magnet
Mass: 12 g
Dimensions
Cylinder: 500 mm long; 50 mm diameter
Long bar: 606 mm long; 12 mm diameter
Small bar: 70 mm long; 10 mm diameter
Ground plate: 199 x 199 x 8 mm3
Warranty:
The 060 Resonance set is warranted to be free from defects in materials and workmanship for a
period of 12 months from the date of purchase provided that it has been used under normal
laboratory conditions. This warranty does not apply if the sensor has been damaged by accident
or misuse.
Note: This product is to be used for educational purposes only. It is not appropriate for
industrial, medical, research, or commercial applications.
Rev. 04/05/12
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