SU1536431A1 - Training aid on physics for investigation of movement of electrons in electric and magnetic fields - Google Patents

Abstract

The invention relates to laboratory training devices and can be used in studying the movement of electrons in electric and magnetic fields. The aim of the invention is to improve the measurement accuracy. The training device contains a cathode ray tube, the electron gun of which is connected to the power supply, horizontal deflection plates are connected to the first source of adjustable voltage, the magnetic deflection system is made in the form of diametrically located conductors placed along the vertical deflection plates coaxially with the neck of the electron beam tube and connected to a regulated current source. The vertical deflection plates are connected to the second variable voltage source through a parallel-connected reference capacitor and switch. Parallel to the vertical deflection plates, a reed switch and an additional capacitor in the form of two parallel plates are connected, the area of which is more than the area of the vertical deflection plates and the distances between the plates are equal. 1 hp f-ly, 1 ill.

Description

The invention relates to laboratory training devices and can be used in studying the movement of electrons in electric and magnetic fields.

The purpose of the invention is to increase the shelf life of the measurement.

The drawing shows the block diagram of the device

The training device contains a cathode-ray tube 1, which includes an electron gun 2, plate 3 horizontal deflection of the beam, plate 4 vertical

beam deflection, power supply unit 5, connected to electron gun 2, variable voltage source 6, connected to horizontal deflection plates 3, magnetic deflection system 7 connected to adjustable current source 8, as well as additional capacitor 9, breaker 10, a reference capacitor 11, a switch 12 and an adjustable voltage source 13, to one output terminal of which one of the vertical deflection plates 4 is connected and the second output

SL

CO C5 4 CO

a terminal through a parallel-connected reference capacitor 11 and a switch 12 is connected to a second vertical deflection plate 4. Reed switch 10 and additional capacitor 9 are connected in parallel with vertical deflection plates 4 Additional capacitor 9 consists of two plane-parallel plates, the area of which is several ten times larger than the vertical deflection plates 4, n the distance between them is equal vertical deflection plates 4 and additional capacitor 9 far exceed the parasitic mounting capacitance, the effect of which during operation of the device can be disregarded. The reed switch 10 is designed to periodically discharge (short-circuit) the vertical deflection plates 4, which eliminates the possibility of electrostatic charging during the operation of the device, distorting the measurement results.

The magnetic deflection system 7 is located on the neck of the electron-beam tube 1 at the level and along the length of the vertical deflection plates 4 and consists of conductors arranged in two diametrically opposite longitudinal grooves cylindrical

Whose dielectric material frame (not specified).

The use of two diametrically opposed sections of the winding ensures, in addition, greater uniformity of the magnetic field in the axial region of the cathode ray tube 1 inside the deflecting system.

The power supply unit 5 of the electron gun 2 provides focusing and regulation of the electron beam brightness, and also allows you to set a certain accelerating voltage UuCK, measured by a kilovoltmeter

The training device is used as follows.

After switching on the device, setting the required luminance and focus, a certain accelerating voltage, Peak, controlled by a kilovolt meter of the power supply unit 5, is established. on which determine the speed V of movement of electrons

zely

l | - m

0 5

0

five

0

50

e

where e is the electron charge; m is the electron mass.

Then, by varying the voltage from the output of the variable voltage source 6, the electron beam is installed in the center of the screen of the cathode ray tube 1 of the switch switch 12, the reference capacitor 11 is short-circuited and by applying voltage from the variable voltage source 13 to the vertical deflection plates 4 create an electric field, which is modeled at a certain frequency with a reed switch 10, the beam is swept across the screen into a 20-30 mm long section up or down from the center of the screen (depending on the floor NOSTA the applied voltage to the plates). Measure the voltage value Unft. Then, in order to create a magnetic field, an electric current is passed through the magnetic deflection system 7 from the source 8 of the controlled current and the current of the segment on the screen of the cathode-ray tube 1 is displaced along this segment by its value in the direction opposite to the initial position relative to the center of the tube. The current I is measured. Without changing the magnitude of the current through the magnetic deflection system 7, the switch 12 is opened. At the same time, the reference capacitor 11 is connected in series with the vertical deflection plates 4 and the capacitor 9. Increasing the voltage from the output of the source 13 of the regulated voltage, the length is restored light segment on the screen of the cathode-ray tube 1. This will occur when the voltage on the vertical deflection plates 4 again becomes equal to Epl.

Determine the equivalent capacitance C of the parallel connection of the plates 4 of the vertical target and the additional capacitor 9 C. Using the formula

C g ek b o

GDR LI - voltage on; graded compound

and C

EK6

 + V

- respectively, the area of the plates 4 nerti "and" - respectively plo

a ball deviation and additional condenser plates 9; L - the distance between the plates, the limit of the electric constant

with% OLi L j "i d

about h 7e, + n y

1 PL П «j

The speed of light in vacuum is determined by the formula

/one

PT (RD) l

1CJL

m

Tfyf; U -l

Claims (2)

Invention Formula one . A teaching device in physics for investigating electrons in electric and magnetic fields, containing a cathode ray tube, an electron gun, is co-ropi and connected to a power supply unit; horizontal deflection plates are connected with f five 0 five 0 The first source of adjustable voltage, the magnetic deflection system, is connected to a source of controlled current, one of the vertical deflection plates is connected directly to the second output terminal of the second source of adjustable voltage, the second output terminal of which is connected to. another vertical deflection plate through a parallel-connected reference capacitor and a switch, characterized in that, in order to improve the measurement accuracy, it is equipped with an additional capacitor and a reed switch connected parallel to the vertical deflection plates, and the area of the additional capacitor plates is larger than the area of the vertical deflection plates, and the distance nor between the plates are equal. 2. An apparatus according to claim 1, characterized in that the winding of the magnetic deflection system is made in the form of parallel conductors placed coaxially with the cathode of the electron-beam tube and diametrically opposed.