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Precision Air Track
P4-2710
Model J2125-B-1.2/B-1.5
1.
Summary
The Air Track works with the principles of an air-cushion. It is used with a Mini-Air Source to
pump air into the hollow space, and there are numbers of air vents on the two working surface of
a hollow track. The compressed air spreads out from the air vents on the working surface of the
track, so the air-cushion forms between the surface of the air track and the inner surface of
glider. Using the air-cushion lubricating reagent, the glider floats stably on the track surface at
any position. Therefore, the relative motion of the glider on the Air Track surface has little loss of
energy along the track. The errors from the friction have been reduced in the experiments and
the experiment precision has been improved, so that the experiment is directly perceived,
authentic, easy for students to understand.
2.
Specifications
2.1 The working length of the Air Track:
1200mm for Air Track Model J2125-B-1.2’
1500mm for Air Track Model J2125-B-1.5;
2.2 The straightness of vertical plane of the track
≤ 0.10mm in all length;
≤±0.05mm at any 400 mm length;
2.3 The angle of the track working surface: 90º~91º;
2.4 The roughness of the surface: Ra3.2;
2.5 The distance between the supporting feet:
600mm for Model J2125-B-1.2;
800 mm for Model J2125-B-1.5;
2.6 The diameter of air vents: φ0.8mm;
2.7 Outer diameter of the hose: φ30mm;
2.8 Glider:
121mm length and about 150g weight
for Model J2125-B-1.2;
156mm length and about 200g weight
for Model J2125-B-1.5;
2.9 The glider floating height: ≥0.10mm (under the air pressure of not less than 5.8kPa).
the max loading mass is not less than 3 times of glider,
2.10 Working ambient temperature: 0ºC ~ +40ºC;
2.11 Relative humidity: ≤85% (40ºC);
2.12 Required Air Source pressure: ≥5.8kPa.
3.
The Characteristics, Construction, Matching
The track is the main body of the Air Track and is made of high alloy aluminum. It is light and of high
mechanical efficiency. The specially designed constructions make it strong and never deforms for over a long
time, guarantee the straightness by precision-processing before being manufactured out of the factory.
The blocked boards at the both ends of the track can be removed so as to clean the inside of the track.
The Photogate is fixed on the both side so that students can observe the experiment easily, as shown as Fig
1.
The accessories are listed in Tab. 1.
4.
Usages and Maintenances
Read this manual and Fig. 1 carefully before the installation. There are many attachments to the Air Track. Try to
know the purpose of every attachment and where it is attached to the Air Track.
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Make sure the lab table is level and stable to install this apparatus. Place the Air Track on the lab table and first
adjust the frame and fix it on the base of the air track by two bolts and the front end with the pulley extends out the
table and connect the Air Source with the back end by the flexible corrugate hose. Place the rise-washer under the
support, the flat side down and the concave side up, and make sure that the supporting and the tip of the adjusting
screw are in the concave.
Fix the pulley on the blocked-board in front of the Air Track and adjust the axle of the pulley on the pulley support
and make it turn freely with appropriate readjustment and if necessary, some lubricating oil.
Connect the Air Source and check if the air can pass through all the air vents on the track by fingers. If the air can
not pass through, the blocking can be removed by a φ0.5mm steel needle. The Air Source is placed on the ground
and far from the table to avoid experiment to suffer the vibration influence.
In some experiments, the glider will repeatedly start from a same position of the track.An adjustable end stopper
in the attachments is used for fixing the position on the track.
During the experiments, 50cm/s is consider an appropriate speed of glider movement.
The bumper can be used for elastic collision labs. In the experiment of the completely inelastic collision, install
the hook stand and the tache on the two gliders separately.
A high standard and precision fit between the surface of the Air Track and the surface of the glider is required.
Use caution to during transportation and installation of the Air Track, to avoid damaging and deforming the surface of
the track and the glider. No moving the glider on the surface of the track before the air blows, to avoid damaging the
surface of the track and glider.
After the experiments, clean the surface of the track and glider with a dry and clean cloth. The Air Track body
must be hanging stored at a vertical condition. Don’t put it where it is damp and or has exposure to corrosive gases.
5.
Possible Experiments
The Air Track is an essential apparatus in secondary school physics lessons and many mechanics in new
textbooks can be performed.
Based on the requirements in the textbooks, following experiments can be done.
1)
Determining the velocity in the uniform rectilinear motion/verifying Newton’s First Law;
2)
Determining the mean velocity and instantaneous velocity in the non-uniform rectilinear
motion;
3)
Determining the acceleration in the uniformly variable rectilinear motion;
4)
Studying the relations between the distance traveled and time taken in the uniformly
variable rectilinear motion;
5)
Determining the gravitational acceleration;
6)
Verifying of Newton’s Second Law.
7)
Verifying of Newton’s Third Law.
8)
Verifying of the theorem of kinetic energy;
9)
Verifying of the theorem of momentum
10)
Verifying of the law of conservation of momentum
11)
Verifying of the law of conservation of mechanical energy;
12)
Study on the law of simple harmonic oscillation
12.1) Determining the coefficient of period stiffness of oscillator (K).
12.2) Verifying the relation of period of simple harmonic oscillation
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12.3) Verifying the relation of amplitude with the period in simple harmonic oscillation.
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5.2 Adjusting the Air Track:
It’s important to adjust the Air Track horizontally level before the experiments. There are two ways
to adjust it.
a.
Static adjusting: The Mini-Air Source is connected. Place the glider on the track and adjust
the adjusting screw repeatedly until the glider is still at any position of the track or it slides
somewhat, but not always in the same direction.
b.
Dynamic adjusting: Adjust the Air Track, together with a model J0201-CC Digital Timer.
Select the function S2 on the Digital Timer. The distance between the two photogates,
which is ≥300mm and are installed on the Air Track. The bumpers are installed at the two
ends of the track. Fix the U-shaped glider flag (10mm) on the glider. Connect the Air
Source. The compressed air flows, so that the glider moves from one end to the other on
the track. It first passes through the two photogates one after the other, then the Timer
records ∆ t1 and ∆ t2.
Adjust the adjusting screw carefully to make the error of ∆ t1 and ∆ t2 is as little as possible. Because of the
air resistance, ∆ t1 is not exactly the same as ∆ t2. If the error (∆ t1 - ∆ t2) from the left to the right is almost the
same as the error (∆ t11 - ∆ t21) from the right to the left, that is (∆ t1 - ∆ t2) = (∆ t11- ∆ t21), the Air Track is
adjusted.
DIGITAL TIMER
MODEL J0201-1
1 Summary:
The digital timer is a precision digital meter for measuring time intervals and a universal meter for
demonstration and measuring time in school physics teaching, also can be used for counting, measuring a period
with an Air Cushion Track Model J2125 set.
The CMOS-IC (DIP package) had been used in this timer, except power supply and light-electricity
converting system.
The crystal-oscillator had been used to be time-base signal, which makes a high precision time counting. The
number can be shown much clearer with the use of digital LEDs. Two pieces of printed circuit make the structure
well-knitted. The shell of the instrument, made of engineering plastic, has a sound exterior and makes the instrument
easy to be examined and adjusted.
2. Technical Specifications:
2.1 Time-base unit: 4Mhz time-base signal oscillation resource was divided into three selection: 0.1ms, l ms
and 10 ms. 0.1ms, measuring range: 000-999X 0.1ms, time-base frequency with precision of 10000Hz ±
5Hz. 1 ms, measuring range: 000-999Xlms, time-base frequency with precision of 1000Hz ± 1Hz. 10ms,
measuring range: 000-99 X 10ms, time-base frequency with precision of 100 ± 1Hz.
2.2 Digital display: 3 digits LED, the visions distance ≤ 5m.
2.3 3Display range: Minimum measurement: 0.1 ms. Maximum measurement: 9.99s.
2.4 Sensor response time: ≤ 0.5µ s.
2.5 Display time and controlling: display any time and manual reset to zero.
2.6 Working condition:
2.6.1 Power: AC 220V + 10%, 50Hz, power consumption: <3W.
2.6.2 Environment temperature: -10 ~ + 40ºC.
2.6.3 Relative humidity: not more than 80% (40ºC).
2.6.4 Working duration: continuous working.
2.7 Size: 230mmX210mmX90mm.
2.8 Weight: < 2kg.
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Fig. 1
3. Construction
3.1 The schematic circuit of the digital timer is shown as Fig 1.
3.2 The schematic printed circuit of the digital timer is shown as Fig 2 and Fig 3 the components of the digital
timer.
3.3 Electrical principles:
3.3.1 Counter, decoder and display unit:
The digital timer (three digits) consists of U53, U511 and digital-LED, clock pulse signals are counted from
U011 to CLK end of U511.
3.3.2 Time-base unit:
It consists of crystal oscillator XTAL, U011 and multistage frequency divider. The time-base signals are given
in three ranges: 0.1ms, 1ms and 10ms, through U013, U18 and U518 frequency divider.
Fig. 2
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Fig. 3
3.3.3 Controlling unit:
It consists of a photo sensor, a Schmitt circuit, a logical circuit and main controlling gate. The photo sensor
consists of 2 silicon phototriodes and 2 infrared emitting diodes (called photo gate). After the signal has been
transited into the instrument, it will be regulated by the Schmitt trigger, and again to be transited to the CLK
end of logical switch U13 and the input of the main controlling gate through the NAND gate.
The shaking of the photo signal edge can be regulated by the Schmitt Trigger.
Turn the switch to S1, the time while the light being covered determines the width of the main controlling
gate U011. Turn the switch to S2 to use each covering light signal as the trigger signal of the controlling
circuit. The width of the main controlling gate signal is determined by the period between two covering light
times.
Turn the switch to J, the timer will count a number while the Photogate being covered.
Turn the switch to T to determine the period, the time of each cycle.
3.3.4 Reset unit:
Manual reset to zero, Push the reset button, zero will be displayed.
3.3.5 Power unit:
The power, IC ± 12V, 400mA, will be supplied to the whole instrument through the 3 terminal Voltageregulator.
4 Usage:
4.1 The front panel as shown as Fig 4.
4.1.1 Function switch K-GN, which can be selected in S1, S2, J and T in the requirements.
4.1.2 Power switch K for ON and OFF.
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4.1.3 Time base selection switch K-SJ can be used for selection of the precision of time base.
4.1.4 Reset button K-RST: reset to zero.
4.1.5 Photo-electric input sockets CZ1, CZ2 can be connected with photogate.
4.2 Turn on power supply, pre-heat for 5 minutes and it starts work after the clock-pulse being stable.
4.3 After power switch K is turned on, “000” will be displayed in three digits LED, Press reset switch, “000”
also to be displayed.
4.4 Switch the band switch K to S1, When two photo-electric plugs are not inserted in the input socket of the
front panel, turn on the power and the LED display timing digits. Then insert two photo-electric plugs into
socket-I and socket –II of the front panel individually, the LED will be stopped displaying, which shows that
the photo gate is working normally. Otherwise, there must be something wrong with the photo gate.
Four-pins socket connections of the photo-electric is shown as Fig 4.
+4.5 Turn Band switch to S2, J or T individually, check the timer through two photo gates.
4.6 Time-base switch K-JS can be selected to different ranges, 0.1ms, 1ms or 10ms. According to the
precision.
4.7 The socket for the time-base frequency output and the ground are on the back cover.
Fig. 4
5 Maintenance:
5.1 Turn off the power, put on the cover after the apparatus being used.
5.2 More attentions to ventilating when the apparatus being used for a higher temperature condition.
5.3 The apparatus is placed in a dry and ventilating place.
5.4 Protect the apparatus from a collision and shaking.
5.5 The CMOS circuits must be turned off before being soldered. The solder must be grounded.
5.6 Open up the cover to examine the inside components and circuits of the instrument.
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6 Contents of the Apparatus Packing Box
No.
Items
Quantity
1
Digital Timer Model J0201-1
1 set
2
Photo-electric gate
2 sets
3
Fuser, 0.2A
2 pieces
4
Humidity protection bag
1
5
Banana-shaped plug
1
6
Pickup plus  3.5
1
7
Instruction Book
1
8
Certificate of quality
1
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©2009 ARBOR SCIENTIFIC ALL RIGHTS RESERVED