SU845829A1 - Electrotherapeutic apparatus - Google Patents

Description

The invention relates to medical equipment, in particular to apparatus for direct current therapy.

Known electrotherapy apparatus containing a constant voltage source, a variable resistor, 5 interconnected measuring device and a polarity switch with a working and auxiliary electrodes and an output transistor Γ1Ί.

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The disadvantage of this apparatus is that at the beginning and at the end of the control range there are abrupt changes in the output current due to the existence of abrupt changes in the resistance characteristic of variable resistors ¹⁵ when the movable contact moves in extreme positions from one material to another having different conductivity.

The purpose of the invention is the exclusion of pain during an abrupt change in the output current ..

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To achieve the goal, a voltage divider is introduced, consisting of a resistor connected to a variable resistor by one terminal and a transistor, while the torus of the latter is connected to the silicon-silicon contact of the variable resistor and to a power source, the emitter is connected to the base of the output transistor and the third output of the resistor, and the base - with a movable contact of a variable resistor, and the polarity switch is connected to the source of the measuring device with a resistor.

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Figure 1 shows a diagram of the apparatus; in Fig. 2, the dependence of the output current on the angle of rotation of the movable contact of the variable resistor; there is no voltage divider in the apparatus; in Fig. Same, a voltage divider is introduced into the apparatus.

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The electrotherapy device of direct current consists of sources 1 and 2 of direct voltage, an alternating resistor 3, which regulates the output current, a measuring device 4, a polarity switch 5 with a working and auxiliary electrodes, an output transistor 6, and a voltage divider consisting of a constant resistor 7 and silicon transistor 8.

In the lower (according to the diagram) position of the variable resistor 3 engine, transistor 8 is open and saturated. The voltage drop across the collector-emitter section is minimal and the base potential of transistor 6 is less than the emitter potential. Transistor 6 is closed, there is no current in the patient circuit. When moving the movable contact of the variable resistor 3 from the lower position to the upper current, the patient’s circuit does not appear until the transistor 8 leaves saturation mode and the base potential of the transistor 6 does not exceed the emitter potential at a certain threshold level determined by its input characteristic. The combination of these initial states of the voltage divider and current-stabilizing transistor provides the appearance of current in the patient circuit when the position of the movable contact of the variable resistor 3 is beyond the bounds of the jump in resistance between the movable and lower fixed contacts. With further movement of the movable contact, the output current of the device gradually increases until the base potential relative to the emitter of transistor 8 decreases to a certain threshold level determined by the input characteristic, and transistor 8 does not enter the cutoff state. Since this threshold level is quite high for silicon transistors, the transistor 8 closes until the resistance changes between the movable and upper fixed contacts of the variable resistor 3. Further movement of the movable contact of the resistor 3 does not increase the output current. The transistor 6 is in this active mode and provides

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- • thereby’s stabilizing the output current over the entire range of its changes.

The use of a voltage divider ₅ with an adjustable division ratio in the apparatus allows for the smooth installation of a stabilized output current in the patient circuit in the entire range of its changes from zero to 10 left to the maximum value, and this, in turn, eliminates the occurrence of pain and thereby improves the quality of At the same time, a wider range of smooth change in the value of the output current allows us to expand the scope of this apparatus by using it not Only for therapy, but also for diagnostics, in particular for determining the tissue sensitivity threshold. Using a voltage divider allows you to ensure the stability of the device in a wide 25 temperature range.

Claims (1)

The invention relates to medical technology, in particular to devices for therapy with direct current. The electrotherapeutic device is known, which contains a constant voltage source, a variable resistor connected to each other, a measuring device and a polarity switch with working and auxiliary electrodes and an output transistor tO. The disadvantage of this device is that at the beginning and at the end of the control range there are abrupt changes in the output current, due to the existence of abrupt changes in resistance characteristic of variable resistors when the moving contact moves to the extreme positions x audio from one another pas material having a different conductivity. The purpose of the invention is to eliminate pain when an output current changes abruptly. To achieve the goal, a voltage divider is inserted, consisting of a resistor, one output connected to a variable resistor, and a silicon transistor, while the collector of the latter is connected to an unconnected contact variable resistor and power supply, the emitter is connected to the base of the output transistor and the eye terminal of the resistor, and the base is connected to the moving contact of the variable resistor, and the field switch is connected to the power source, and PSI the output ican m. Figure 1 shows the electrical circuit of the apparatus; Fig. 2 is a graph of output current versus rotation angle of a moving contact of a variable resistor; a voltage divider is absent in the device; On the fi the same, a voltage divider is introduced into the device. Electrotherapeutic device of direct current consists of sources and 2 constant voltage, variable resistor 3, regulating output current, measuring device 4, switch 5 polarity with working and auxiliary electrodes, output transistor 6 and voltage divider Sch of a constant resistor 7 and a silicon transistor 8. In the center (according to the diagram) the position of the slider of the 3 resistor 13 PST 8 is open and saturated. The voltage drop across the collector-em ter is minimal and the potential of the base of transistor 6 is less than the potential of the emitter. The transistor 6 is closed, there is no current in the patient circuit. When moving the moving contact of the variable resistor 3 from the bottom of the burner to the upper current in the patient circuit does not appear until the transistor 8 goes out of saturation mode and the base potential of transistor 6 does not constitute the emitter potential to a certain threshold level, emy its input characteristic. The combination of the initial state data of the voltage divider and the current stabilizing transistor provides the current in the patient's circuit when the moving contact of the variable resistor 3 is over the boundary of the step-like change in resistance between the moving and lower fixed contacts. Upon further movement of the moving contact, the output current of the apparatus gradually increases until the base potential relative to the emitter of transistor 8 decreases to a certain threshold level determined by the input characteristic and the transistor 8 does not enter the cut-off state. Since silicon transistors have this threshold level high enough, transistor 8 shuts down before a sudden change in resistance between the moving and upper fixed contacts of the alternating resistor 3. Moving the moving contact of resistor 3 further does not increase the output current. At the same time, transistor 6 is in active mode and provides 4 thereby stabilizing the output current in the whole range of its changes. The use of a voltage divider with an adjustable division factor in the device allows a smooth installation of a stabilized output current in the patient's circuit over the entire range of its changes from zero to maximum, and this in turn eliminates the occurrence of pain and thereby improves quality along with this, a wider range of smoothly varying output current magnitude allows the scope of application of this apparatus to be expanded by using it It is useful for therapies, but also for diagnostics, in particular for determining the tissue sensitivity threshold. The use of a voltage divider makes it possible to ensure the stability of the apparatus operation over a wide range of temperatures. The invention The electrotherapeutic device, comprising a source of voltage, a variable resistor, a measuring device and a polarity switch with a working and auxiliary electrodes, and an output transistor, characterized in that, in order to eliminate pain when an output current changes abruptly, A voltage divider consisting of a resistor, one output connected to a variable resistor, and a silicon transistor is inserted into it, while the collector of the latter is connected to The contact resistor and power source, the emitter is connected to the output transistor base and the second output of the resistor, and the base to the moving contact of the variable resistor, the polarity switch being connected to the power source and the measuring device to the output transistor. Sources of information taken into account during the examination 1. USSR Author's Certificate No. 213987, cl. A 61 N 1/34, 1966.