RU2036548C1 - Low-voltage arc producer - Google Patents

Abstract

FIELD: educational electrical engineering appliances. SUBSTANCE: producer has primary oscillatory circuit built up of capacitors C₁, C₂,, diode D₁,, resistor R₁, thyristor T, primary winding of high-voltage transformer Tr₂, and second tuned circuit inductively coupled with the former and built up of capacitors C₃, C₄, C₅,, diodes D₂, D₃, D₄, resistors R₂, R₃, R₄, and secondary winding of transformer. Novelty is replacement of 220/2000 V transformer designed for feeding high-voltage circuit by two pairs of capacitors connected into pulse voltage doubling circuit affording two-stage firing of low-voltage arc and creation of discharge circuit set up of storage capacitor, two diodes, two resistors supplied with power from 42/220 V low-power transformer in case of high duty factor of low-voltage arc pulses. EFFECT: improved safety in operation. 2 dwg

Description

 The invention relates to electrotechnical teaching aids, in particular to writing instruments, which are used to record information on the movement of bodies in the form of cinograms with a pulsed current on ordinary paper and intended to study mechanics at school.

 Analogs are known for producing cinemograms by three types of electrical discharges: a high-voltage spark, which burns through poorly visible holes in ordinary paper; a high-frequency spark on heat-sensitive paper, the cinemogram of which cannot be projected onto the screen; a pulsed electric arc, which is powered by a 220 V network, and therefore school students are not allowed to use it.

 As a prototype, an electric circuit of a pulsed electric arc was chosen, which operates in the equal mode of a low-voltage spark, when the capacitor shunting the network from a high-frequency current has not tenths of microfarads, but about 10 or more microfarads. The prototype contains a high frequency electric oscillation generator, which has a circuit consisting of a secondary winding of a high voltage transformer 220/2000 V, a primary winding of a high frequency transformer, a spark gap and a capacitor connected in parallel with the secondary winding of a high voltage transformer. The prototype also contains a low-voltage spark generator, consisting of a storage capacitor charging circuit having a 220 V AC source, a resistor, a storage capacitor, and also contains a discharge circuit consisting of the same capacitor, a secondary winding of a high-frequency transformer, and a low-voltage spark gap.

 However, the known electrical circuit is powered by a 220 V network voltage, which is dangerous for a student, and cannot operate from a school network of 42 V or lower. It does not allow you to change the burning time of the pulse of a low-voltage spark, and therefore does not allow you to adjust the size of the holes burned by a low-voltage spark in the paper, and therefore, to obtain high-quality cinema images. In addition, this scheme does not allow the construction of portable school safe devices weighing several hundred grams due to the large weight and size of the high-voltage transformer.

 The aim of the invention is the creation of a portable and safe device for receiving a low-voltage spark powered from a school network of 42 V and below, improving the quality of cinemograms by regulating the size of holes burned through a low-voltage spark in paper, and also creating a device for students with which they could perform on physics lessons quantitative experiments in the study of mechanics at the modern technical level.

 To do this, instead of a 220 V network, which is dangerous for students, a low-power transformer is used, powered by a school network of 42 V and below and an accumulative capacitor, and instead of a high-voltage transformer weighing about 3 kg, two small pairs of capacitors, two diodes and two resistors are used, instead of a spark gap it is used thyristor.

 The first distinguishing feature is that to increase operational safety, the device is powered by a low-power transformer connected to the school low-voltage network, the diode and resistor are additionally included in the storage circuit of the storage capacitor of the low-voltage spark generator, and the diode and variable are additionally included in the discharge circuit of the storage capacitor resistance.

 The second distinctive feature of the device is that, in order to reduce weight and size, a second capacitor and a first diode and a first resistor for doubling the voltage are introduced in series with the first capacitor instead of a high-voltage transformer, instead of a high-voltage transformer, and a thyristor is introduced instead of the spark gap opened by a frequency divider. To increase air ionization in the gap of the spark gap, a second auxiliary circuit was created containing the third and fourth capacitors connected by a second diode and a second resistor according to a voltage doubling circuit, and a spark gap and a secondary winding of a high-frequency transformer are connected in series with them.

 Figure 1 shows an electrical diagram of a device for producing a low-voltage spark; figure 2 cinematic uniform motion recorded by a low-voltage spark.

PRI me R. A device for producing a low-voltage spark contains: transformers: Tr1 42/220 V, 40 W. TP2 high-frequency transformer with a ferrite core. L1 15 turns, L2 450 turns;
capacitors C1 C2 C3C4 = 0.25 uF; C5 20 uF;
diodes D1 D2 KD 105G; D3 D4 D246;
thyristor T T 6 10 8;
resistors R1 R2 2.5 kOhm; R3 100 ohms; R4 100 ohms (variable);
low-voltage spark gap P homemade (gap 1 mm).

 The electrical circuit works as follows.

 After the device is connected to the 42 V network, C2 and C4 are charged to a constant voltage of about 300 V. The capacitors C1 and C3 are constantly recharged with a voltage of 220 V. Therefore, the voltage on C1, C2 and C3, C4 pulsates from 0 to about 600 V. Simultaneously, gradual charging of capacitor C5. At predetermined current periods set by the frequency divider, the thyristor T opens and C1 and C2 are discharged through the coil L1. This is how low-power, high-frequency, rapidly damped, oscillations with a frequency of about 100 kHz arise in the C1, C2, L1, and T circuits. The voltage of these oscillations on the winding L1 with the help of Tp2 rises to about 8000 V and is transmitted to the circuit L2, C3, C4, P. The created voltage breaks the air gap of the spark gap P and partially ionizes it, but enough to discharge C3 and C4 through it at 600 V at this moment. Two-stage ionization is carried out so that the device can ignite the low-voltage spark created by the discharge of capacitor C5.

 The burning time of the pulse of a low-voltage spark, and consequently, the size of the holes of marks burned in the paper (see figure 2), is set by the variable resistance R4.

Claims (1)

 A device for producing a low-voltage spark containing a spark generator of electrical oscillations of high frequency, which includes the first and second input terminals, which are terminals for connecting a power source, a high-frequency transformer, the first and second terminals of the secondary winding of which are respectively the first and second terminals of its output, the first the terminal of the primary winding of which through the first spark gap is connected to the first terminal of the input of the spark generator of electrical oscillations of high frequency and the first a capacitor, as well as a first resistor, a discharge channel, which includes a first, second and third input terminal, a first output terminal, a second resistor and a second capacitor, the first and second terminals of a second capacitor connected respectively to the first and third input terminal of the discharge channel, the first and second the terminals of the input of the discharge channel are terminals for connecting the power source, the second spark gap, the first terminal of which is connected to the first terminal of the output of the spark generator of electrical oscillations of high frequency and in-line channel, the second and third terminals of the output and input respectively of which are connected, characterized in that, in order to improve safety during operation, a third capacitor, a first diode and a frequency divider are introduced into the spark generator of high-frequency electric oscillations, and a control terminal is inserted into the first spark gap moreover, the first input terminal of the spark generator of electrical oscillations of high frequency through connected in series the first diode and resistor is connected to the second terminal of the primary winding of the high-frequency transformer, which is connected through the third capacitor to the second input terminal of the spark generator of high frequency electric oscillations and the first capacitor, the first and second input terminals of the frequency divider are connected respectively to the first and second terminals of the input, spark generator of high frequency electric oscillations, the first and second divider output terminals the frequencies are connected respectively to the first terminal of the first capacitor and the control terminal of the first spark gap, the second, third and fourth are introduced into the discharge channel th diodes, third resistor, variable resistor, fourth and fifth capacitors, the second terminal of the input of the discharge channel is connected directly to the second terminal of the second capacitor and through the second diode and resistor and the fourth capacitor connected in series with the first terminal of its input, which is through the third diode and the third a resistor, a fourth diode and a variable resistor connected to the second terminal of the second spark gap, which is connected to the first terminal of the fourth capacitor, the third terminal of the input of the discharge channel through the fifth condensers connected to a second terminal of the third resistor, and the first and second input terminals of the spark generator of high frequency electrical oscillations and the discharge channel respectively connected.

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