Dot Timer Experiment Report, How to Do Dot Timer Experiment?

Equipment: dot timer, long wooden board with pulley attached to one end, trolley, paper tape, string, hook code, scale, wire, power supply.

Steps:1Place the long wooden board flat on the experimental table, make the pulley protrude from the table, fix the dot timer on the long wooden board without the end of the pulley, and connect the electrical circuit.

2.Tie a string to the trolley so that the rope crosses the pulley and hangs the appropriate hook code underneath. Thread the paper tape through the dot timer, and fix one end of the paper tape behind the trolley.

3.Park the trolley close to the dot timer, turn on the power, let go of the trolley, let the trolley drag the paper tape to move, and the dot timer will put a column of dots on the paper tape. Replace with a new paper tape and repeat the experiment three times.

4.Choose one of the three paper tapes that is ideal, discard some of the denser points at the beginning, and find a starting point in the back that is convenient for measuring, and determine the counting point.

The EDM timer replaces the electromagnetic dot timer for experiments.

Purpose and Requirements].

Understand the working principle of the EDM timer, master the method of operating the EDM timer, and use the EDM timer to carry out mechanical group experiments and group experiments in the classroom.

Instruments and equipment].

EDM timer, simple EDM tracker.

Experimental method] 1 The toner paper tray with an outer diameter of 38 mm and a diameter of 2 2 mm in the center hole (hereinafter referred to as the paper tray) is packed under the paper pressure strip; When loading, the elastic card should be moved slightly outward, and then the paper strip should be removed, and the center hole of the paper tray should be set on the paper plate shaft, and then the paper strip should be reset.

2 Cut the ordinary white paper into (20 05) 700 mm2 paper tape 1, pass under the paper tray, and the same paper tape 2 passes through the paper tray, when the two paper tapes are folded together and move in the direction of the paper tape, the toner paper disc can be easily driven to rotate. As shown in Figure 2 10 3.

3 Clamp the folded paper tapes 1 and 2 to the moving object about 80 mm away from the EDM timer. Holding the paper tape in one hand is ready to control the starting of the object. Press the EDM timer with the palm of your other hand and hold your fingers on either side.

Press the pulse output switch with one finger, you can hear a slight discharge sound at this time, you can release the finger of the paper tape, let the moving object drag the paper tape through the discharge gap, and record the displacement of the moving object every 0 02 seconds.

4. Remove the paper tape 1 to view the recorded dot trace, its data collection and processing method is the same as that of the electromagnetic dot timer. When the toner carton is used dozens of times, it should be replaced with another one to avoid unclear traces or leakage.

5 In the above-mentioned dotting process, the pulse current is connected to the discharge needle of the positive electrode, through the white paper tape 1, the toner paper tray, to the paper disc shaft connected to the negative electrode, see Figure 2 10 4. Alternatively, instead of a toner paper tray, (20 05) 700 mm2 toner paper tape is sandwiched between two white paper tapes.

Understand the construction of a dot timer; A dot timer will be used to study the law of the change of the speed of the object with the slip of time; By analyzing the paper tapeDetermine the acceleration of linear motion with uniform variable speed and its velocity at a certain moment; Learn to use image method and list method to process experimental data.

First, the purpose of the experiment.

1. Practice using the dot timer and learn to study the movement of objects with dotted paper tape.

2. Measure the acceleration of linear motion at uniform variable speed.

Second, the principle of experiment.

1. Electromagnetic dot timer.

Operating voltage: 4-6V AC power supply.

Dotting period: t=, f=50 Hz.

2. EDM timing cavity gripper.

Operating voltage: 220V AC power supply.

Dotting period: t=, f=50 Hz.

Dotting principle: it uses spark discharge to make a small hole in the paper tape and display the timer of the dots, when the 220V AC power supply is turned on, when the pulse output switch is pressed, the pulse current sent by the timer passes through the discharge needle of the positive pole, the toner paper tray is connected to the paper tray shaft connected to the negative pole, and an electric spark is generated, so a series of dot traces are laid on the paper tape.

3. Experimental equipment.

Trolley, string, hook code, long wooden board with fixed leather bucket pulley attached to one end, EDM dot timer (or dot timer), low-voltage AC power supply, two wires, paper tape, meter ruler.

Here are five steps.

The following basic steps are used in experiments that use a dot timer to analyze the motion of an object:

1. Fix the dot timer on the table.

2. Install the paper tape.

3. Turn on the low-voltage AC power supply.

4. Remove the paper tape.

5. Loosen the paper tape to let the object move with the paper tape.

6. Disconnect the switch.

The movement of the paper tape dragged by the trolley was recorded with a dotting timer, and a total of 7 counting points of A, B, C, D, E, F, G were determined on the paper tape to be covered and held The distance between its adjacent points is shown in the figure, and there are still 4 print points between every two adjacent counting points that are not drawn.

Try to calculate the instantaneous speed of the trolley when hitting five points of B, C, D, E, F according to the distance between each counting point on the paper tape, and fill in the following table with each speed value to keep 3 significant digits

<> the instantaneous pure celebratory velocity of B, C, D, E, F at each moment is marked in the Cartesian coordinate system, and the relationship between the instantaneous speed of the car and the time is drawn

From the drawn velocity-time image, the acceleration of the trolley is a=k=.

I guess you can just read a book, are you listening in class, depressed.

1.Place the long plank flat on the lab table with the pulleys protruding from the table.

2.Fix the dot timer on the side of the board without pulleys and connect it to the circuit.

3.Tie a string to the trolley, and the rope is crossed over the fixed pulley, and the appropriate hook code is hung underneath.

4.Attach the paper tape that runs through the dot timer to the back of the trolley.

5.Make the trolley stop close to the dot timer, turn on the power, let go of the trolley, and let the trolley move.

6.Disconnect the power supply and remove the paper tape.

7.Replace with a new tape and redo it twice.