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Smart Timer

012–06734A

4

Pla

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Operating the Smart Timer

1. Plug the ¼-inch phone plug from the photogate into the

Smart Timer’s input channel 1 or 2 (see Figure 2). For all

experiments using a single photogate or pulley, either of the

two available jacks may be used interchangeably. For all

other modes see the individual descriptions below.

2. Plug the 9 VDC power adapter into the small receptacle on

the side of the timer and into a standard 110 VAC, 60 Hz

wall outlet.

3. Position the photogate head so the object to be timed will

pass through the arms of the photogate, blocking the

photogate beam.  Loosen the clamp screw if you want to

change the angle or height of the photogate, then tighten it

securely.

4. Slide the power switch to the ON position. The Smart

Timer will “beep” and show PASCO scientific on the

display. From this point, the  three-step setup of the Smart

Timer is easy:

1. Press the Select Measurement key until the

desired measurement type is displayed on the top

line of the display. Note that the menu rolls over to

the beginning after the last type is selected.

2. Press the Select Mode key until the measurement

mode is displayed after the measurement type.

You cannot begin a measurement until both the

type and mode have been selected.

3. Once a complete measurement has been selected,

press Start/Stop to begin. You will hear a “beep”,

and a asterisk (*) will appear on the second line of

the display. In most modes, the (*) indicates that

the Smart Timer is now waiting for an event to

occur, like a fence passing through a photogate.

5. If an event occurs, the Smart Timer beeps again, displays a

result, and the (*) disappears. Pressing Start/Stop before an

event occurs will remove the (*) and allow you to change

the measurement type.

Smart Timer Modes of Operation

 The Smart Timer has 18 modes of operation organized into five

groups:  TimeSpeedAccelerationCounts, and Test. A

Figure 2

Connecting the photogate to the Smart
Timer

ä Important Setup Note:
The Smart Timer incorporates a feature to

increase the battery lifetime. The photogate

turns on only when Start/Stop is pressed

to start an experiment. Photogate power is

turned off when the measurement is

complete or the operator presses Start/

Stop. The exception is the Test mode in

which photogate power is turned on as

soon as the display reads Test:Gates and is

not turned off until Select Measurement is

pressed again. Setup for the experiment is

often best accomplished in Test:Gates

mode.

input channel 2

input channel 1

 Note:  Smart Timers shipped to certain

locations are supplied with a  transformer
for 220/240 VAC, 50 Hz power.

Summary of Contents for ME-8932

Page 1: ...1998 PASCO scientific 7 50 Instruction Manual and Experiment Guide for the PASCO scientific Model ME 8930 012 06734A 09 98 SMART TIMER Plane4...

Page 2: ...Smart Timer 012 06734A...

Page 3: ...SpeedMeasurementModes 7 Table 1 Summary of Timing Modes 8 9 AccelerationMeasurementModes 10 Count Modes 10 Test Mode 11 Timing Diagrams 11 LOCK Switch 11 Caring for the Smart Timer 12 Specifications 1...

Page 4: ...he equipment for return shipment will not be covered by the warranty Shipping costs for returning the equipment after repair will be paid by PASCO scientific Copyright Warranty and Equipment Return Pl...

Page 5: ...existing timing options The Smart Timer s internal microcontroller also eliminates the problem of incorrect readings due to multiple passes through the same photogate by understanding the type of mea...

Page 6: ...to a glide or Dynamics Cart the Smart Timer and Smart Pulley can be used to determine linear acceleration cm s2 as well Note The use of pulleys with different diameters and or different number of spo...

Page 7: ...display touchpad keys mode illustrations on off switch side panel battery compartment bottom panel input channel 2 input channel 1 connector for 9VDC adapter side panel 9 VDC adapter Figure 1 Include...

Page 8: ...measurement until both the type and mode have been selected 3 Once a complete measurement has been selected press Start Stop to begin You will hear a beep and a asterisk will appear on the second lin...

Page 9: ...012 06734A Smart Timer 5...

Page 10: ...essing Start Stop will stop the measurement and any recorded times will be displayed Two Gates In this mode the Smart Timer measures the time between blocking two photogates This mode is useful for no...

Page 11: ...iming with the Start Stop key and end it with a photogate block or vice versa 4 If a photogate is plugged in and blocked when you try to use the Start Stop key as a stopwatch the Smart Timer will be t...

Page 12: ...Gate Fence Two Gates Pendulum Stop Watch One Gate cm s Collision cm s Pulley rad s Pulley rev s Table 1 Summary of Smart Timer Modes Time Speed Type Modes Key Sequence Timing Diagram Calculation Algor...

Page 13: ...One Gate Linear Pulley Angular Pulley Two Gates 30 seconds 60 seconds 5 minutes Manual One Gate Acceleration Counts Test The key sequences shown are valid in the initial or power on situation only...

Page 14: ...e the radians second measurement there is a two second maximum time for two photogate blocks translating to a minimum speed of 0 05 rev s Also note that accuracy decreases rapidly as pulley speeds inc...

Page 15: ...owered as long as the top line of the display reads Test Gates This mode is useful for experiment setup or for testing accessory photogates G M tubes or other Smart Timer accessories Pressing the Sele...

Page 16: ...ing resolution of the Smart Timer is 100 microseconds in all modes except Stopwatch which is 10 ms Calculated Values Calculated values are displayed to one or two decimal places with typical accuracy...

Page 17: ...rt Timer so you get more accurate measurements of the free fall time of the steel ball See page 34 Determining the acceleration due to gravity g with the Free Fall Adapter and Figure 10 1 for details...

Page 18: ...Smart Timer 012 06734A 14...

Page 19: ...directly To calculate the acceleration from time measurements the following formula must be used Note that Dt is not t2 but is 1 2 t2 see Figure 1 1 Figure 1 1 Explanation of why t2 is used in the for...

Page 20: ...t accuracy 1 The Picket Fence must be dropped at a 90 angle to the photogate beam in such a way that it does not rotate on the way down One method to improve the drop is to hold the edge of the Picket...

Page 21: ...g assuming that friction is negligible According to Newton s Second Law this net force should be equal to ma where m is the total mass that is being accelerated which in this case is m1 m2 This experi...

Page 22: ...will begin when the photogate beam is first blocked Repeat this measurement 3 times with the same masses Record all the values in Table 2 1 Calculate the average accelerations and record in Table 2 1...

Page 23: ...er accomplished in this experiment using the Velcro patches on one end of each cart Procedure PARTA Inelastic Collisions 1 Level the track by setting a cart on the track to see which way it rolls Adju...

Page 24: ...e of the track Give the other cart an initial velocity toward the cart at rest b Start both carts at one end of the track Give the first cart a slow velocity and the second cart a faster velocity so t...

Page 25: ...e total momentum of the carts before and after the collision and record in the table Questions Table 3 2 Results 1 When two carts moving toward each other have the same mass and the same speed they st...

Page 26: ...ut two mass bars in one of the carts so that the mass of one cart 3M is approximately three times the mass of the other cart 1M Weigh the carts and record the masses in Table 3 3 a Place the 3M cart a...

Page 27: ...al 3 Trial 4 Trial 5 Trial 6 Trial 7 Table 3 4 Results Questions 1 Kinetic energy is not conserved in inelastic collisions but it is conserved in ideal elastic collisions For one of the collisions cal...

Page 28: ...Smart Timer 012 06734A 24...

Page 29: ...theoreticalvalues Theory Theoretically the rotational inertia I of a ring about its center of mass is given by where M is the mass of the ring R1 is the inner radius of the ring and R2 is the outer ra...

Page 30: ...rT where r is the radius of the 3 Step Pulley about which the thread is wound and T is the tension in the thread when the apparatus is rotating Applying Newton s Second Law for the hanging mass m giv...

Page 31: ...he acceleration of the ring and disk using a hanging mass of about 50 g Wind the thread up and let the mass fall Record the acceleration press when the mass has fallen about 1 3 of the total fall dist...

Page 32: ...ving only the rotational inertia of the ring To do this take the ring off the rotational apparatus and repeat step 2 using a hanging mass of approximately 30 g 5 Remove the disk from the shaft and rot...

Page 33: ...onal inertia of the ring and disk Note This calculation will be the rotational inertia of the ring alone 5 Calculate the experimental value of the rotational inertia of the disk about its diameter 6 C...

Page 34: ...Smart Timer 012 06734A 30...

Page 35: ...12 05035 Acceleration Down an Incline Experiment 8 Use a Photogate and the Smart Timer instead of a stop watch Figure 5 1 Adjust the height of the Photogate so the light path is intersected with the 5...

Page 36: ...t oscillations and activate the Smart Timer to measure the period of oscillation Note The following experiment is in copy ready form in the manual for the Introductory Dynamics System with Computer Ti...

Page 37: ...riment 2 Use the Smart Timer instead of a computer and IDS Timer software and set the experiment up as directed in the experiment Plug the photogates into the Smart Timer as shown in Figure 8 1 and se...

Page 38: ...or 2 of the Smart Timer Figure 10 1 Set up the Stopwatch mode of the Smart Timer Press once The Smart Timer is now activated and will record the time the interval between the release of the ball and...

Page 39: ...pasco com Contacting Technical Support Before you call the PASCO Technical Support staff it would be helpful to prepare the following information If your problem is with the PASCO apparatus note Titl...

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