♦ As we have already found out, a thyristor is a semiconductor device that has the properties of an electric valve. Thyristor with two terminals (A - anode, K - cathode) , this is a dinistor. Thyristor with three terminals (A – anode, K – cathode, Ue – control electrode) , this is a thyristor, or in everyday life it is simply called a thyristor.

♦ Using the control electrode (under certain conditions), you can change the electrical state of the thyristor, that is, transfer it from the “off” state to the “on” state.
The thyristor opens if the applied voltage between the anode and cathode exceeds the value U = Upr, that is, the magnitude of the breakdown voltage of the thyristor;
The thyristor can be opened at a voltage less than Upr between anode and cathode (U< Uпр) , if you apply a voltage pulse of positive polarity between the control electrode and the cathode.

♦ The thyristor can remain in the open state for as long as desired, as long as the supply voltage is applied to it.
The thyristor can be closed:

• - if you reduce the voltage between the anode and cathode up to U = 0;
• - if you reduce the anode current of the thyristor to a value less than the holding current Iud.
• — by applying a blocking voltage to the control electrode (only for turn-off thyristors).

The thyristor can also remain in the closed state for any length of time until the triggering pulse arrives.
Thyristors and dinistors operate in both direct and alternating current circuits.

Operation of dinistor and thyristor in DC circuits.

Let's look at some practical examples.
The first example of using a dinistor is relaxation sound generator .

We use it as a dinistor KN102A-B.

♦ The generator works as follows.
When the button is pressed Kn, through resistors R1 and R2 The capacitor gradually charges WITH(+ batteries – closed contacts of the Kn button – resistors – capacitor C – minus batteries).
A chain of a telephone capsule and a dinistor is connected in parallel to the capacitor. No current flows through the telephone capsule and the dinistor, since the dinistor is still “locked”.
♦ When the capacitor reaches the voltage at which the dinistor breaks through, a pulse of capacitor discharge current passes through the coil of the telephone capsule (C - telephone coil - dinistor - C). A click is heard from the phone, the capacitor is discharged. Next, capacitor C charges again and the process repeats.
The frequency of repetition of clicks depends on the capacitance of the capacitor and the resistance value of the resistors R1 and R2.
♦ With the voltage, resistor and capacitor ratings indicated on the diagram, the frequency of the sound signal using resistor R2 can be changed within 500 – 5000 hertz. The telephone capsule must be used with a low-impedance coil 50 – 100 Ohm, no more, for example a telephone capsule TK-67-N.
The telephone capsule must be connected with correct polarity, otherwise it will not work. On the capsule there is a designation + (plus) and – (minus).

♦ This scheme (Figure 1) has one drawback. Due to the large spread of dinistor parameters KN102(different breakdown voltage), in some cases, it will be necessary to increase the power supply voltage to 35 – 45 volts, which is not always possible and convenient.

A control device assembled on a thyristor for turning on and off the load using one button is shown in Fig. 2.

The device works as follows.
♦ In the initial state, the thyristor is closed and the light does not light.
Press the Kn button for 1 – 2 seconds. The button contacts open, the thyristor cathode circuit is broken.

At this moment the capacitor WITH charged from a power source through a resistor R1. The voltage across the capacitor reaches U power supply.
Release the button Kn.
At this moment, the capacitor is discharged through the circuit: resistor R2 - control electrode of the thyristor - cathode - closed contacts of the Kn button - capacitor.
Current will flow in the control electrode circuit, thyristor "will open".
The light comes on and along the circuit: plus batteries - load in the form of a light bulb - thyristor - closed contacts of the button - minus batteries.
The circuit will remain in this state for as long as desired. .
In this state, the capacitor is discharged: resistor R2, transition control electrode - thyristor cathode, contacts of the button Kn.
♦ To turn off the light bulb, briefly press the button Kn. In this case, the main power supply circuit of the light bulb is interrupted. Thyristor "closes". When the contacts of the button are closed, the thyristor will remain in the closed state, since on the control electrode of the thyristor Uynp = 0(capacitor is discharged).

I have tested and worked reliably various thyristors in this circuit: KU101, T122, KU201, KU202, KU208 .

♦ As already mentioned, the dinistor and thyristor have their own transistor analogue .

The thyristor analogue circuit consists of two transistors and is shown in Fig. 3.
Transistor Tr 1 has p-n-p conductivity, transistor Tr 2 has n-p-n conductivity. Transistors can be either germanium or silicon.

The thyristor analogue has two control inputs.
First entry: A – Ue1(emitter - base of transistor Tr1).
Second entrance: K – Ue2(emitter - base of transistor Tr2).

The analogue has: A - anode, K - cathode, Ue1 - the first control electrode, Ue2 - the second control electrode.

If control electrodes are not used, then it will be a dinistor, with electrodes A - anode and K - cathode .

♦ A pair of transistors, for an analogue of a thyristor, must be selected of the same power with a current and voltage higher than that required for the operation of the device. Thyristor analog parameters (breakdown voltage Unp, holding current Iyд) , will depend on the properties of the transistors used.

♦ For more stable analog operation, resistors are added to the circuit R1 and R2. And using a resistor R3 breakdown voltage can be adjusted Upr and holding current Iyd analogue of a dinistor - a thyristor. A diagram of such an analogue is shown in Fig 4.

If in the audio frequency generator circuit (Figure 1), instead of a dinistor KN102 turn on the dinistor analogue, you get a device with different properties (Figure 5) .

The supply voltage of such a circuit will be from 5 to 15 volts. Changing resistor values R3 and R5 You can change the tone of the sound and the operating voltage of the generator.

Variable resistor R3 The breakdown voltage of the analogue is selected for the supply voltage used.

Then you can replace it with a constant resistor.

Transistors Tr1 and Tr2: KT502 and KT503; KT814 and KT815 or any others.

♦ Interesting voltage stabilizer circuit with load short circuit protection (Figure 6).

If the load current exceeds 1 ampere, the protection will work.

The stabilizer consists of:

• - control element - zener diode KS510, which determines the output voltage;
• - actuator transistors KT817A, KT808A, acting as a voltage regulator;
• - a resistor is used as an overload sensor R4;
• — the actuator protection mechanism uses an analogue of a dinistor, on transistors KT502 and KT503.

♦ At the input of the stabilizer there is a capacitor as a filter C1. Resistor R1 the stabilization current of the zener diode is set KS510, size 5 – 10 mA. The voltage across the zener diode should be 10 volts.
Resistor R5 sets the initial mode of output voltage stabilization.

Resistor R4 = 1.0 Ohm, is connected in series to the load circuit. The greater the load current, the more voltage proportional to the current is released across it.

In the initial state, when the load at the output of the stabilizer is small or turned off, the thyristor analogue is closed. The voltage of 10 volts applied to it (from the zener diode) is not enough for breakdown. At this moment the voltage drop across the resistor R4 almost equal to zero.
If you gradually increase the load current, the voltage drop across the resistor will increase R4. At a certain voltage on R4, the thyristor analogue breaks through and the voltage is established between the point Point1 and a common wire equal to 1.5 - 2.0 volts.
This is the voltage of the anode-cathode transition of an open analogue of a thyristor.

At the same time the LED lights up D1, signaling an emergency. The voltage at the output of the stabilizer, at this moment, will be equal to 1.5 - 2.0 volts.
To restore normal operation of the stabilizer, you need to turn off the load and press the button Kn, resetting the security lock.
There will be voltage again at the output of the stabilizer 9 volts, and the LED will go out.
Setting the resistor R3, you can select the protection operation current from 1 ampere or more . Transistors T1 and T2 Can be installed on one radiator without insulation. The radiator itself should be isolated from the housing.

Dinistors are a type of semiconductor devices, more precisely, uncontrolled thyristors. In its structure it contains three p-n junctions and has a four-layer structure.

It can be compared to a mechanical key, that is, the device can switch between two states - open and closed. In the first case, the electrical resistance tends to very low values, in the second, on the contrary, it can reach tens and hundreds of Mohms. The transition between states occurs abruptly.

In contact with

Dinistor DB 3

This element is not widely used in radio electronics, but is still often used in circuits of devices with automatic switching, signal converters and relaxation oscillation generators.

How does the device work?

To explain the principle of operation of the db 3 dinistor, let us designate the p-n junctions present in it as P1, P2 and P3, following the circuit from the anode to the cathode.

In the case of direct connection of the device to the power source, the forward bias falls on transitions P1 and P3, and P2, in turn, begins to work in the opposite direction. In this mode, db 3 is considered closed. The voltage drop occurs at the P2 junction.

The current in the closed state is determined by the leakage current, which has very small values ​​(hundredths of mA). A slow and gradual increase in the applied voltage, up to the maximum off-state voltage (breakdown voltage), will not contribute to a significant change in current. But when this voltage is reached, the current increases abruptly, and the voltage, on the contrary, drops.

In this mode of operation, the device in the circuit acquires minimum resistance values ​​(from hundredths of an ohm to units) and begins to be considered open. In order to close the device, you need to reduce the voltage on it. In a reverse connection circuit, transitions P1 and P3 are closed, P2 is open.

Dinistor db 3. Description, characteristics and analogues

Dinistor db 3 is one of the most popular types of uncontrolled thyristors. It is most often used in voltage converters of fluorescent lamps and transformers. The operating principle of this device is the same as that of all uncontrolled thyristors, the only differences are in the parameters.

Device characteristics:

• Open dinistor voltage – 5V
• Maximum open dinistor current – ​​0.3A
• Pulse current in open state – 2A
• The maximum voltage of a closed device is 32V
• Current in a closed device – 10A

Dinistor db 3 can operate at temperatures -40 to 70 degrees Celsius I.

Check db 3

Failure of such a device is a rare event, but nevertheless it can still happen. Therefore, checking the db 3 dinistor is an important issue for radio amateurs and radio equipment repairers.

Unfortunately, due to the technical features of this item, You won't be able to check it with a regular multimeter.. The only action that can be implemented using the tester is dialing. But such a check will not give us accurate answers to questions about the functionality of the element.

However, this does not mean that checking the device is impossible or simply difficult. For a truly informative check about the state of this element, we need to assemble a simple circuit consisting of a resistor, an LED and the dinistor itself. We connect the elements in series in the following order - the anode of the dinistor to the power supply, the cathode to the resistor, the resistor to the anode of the LED. An adjustable unit with the ability to raise the voltage to 40 volts must be used as a power source.

The verification process according to this scheme consists of gradually increasing the voltage at the source in order to light up the LED. In the case of a working element, the LED will light up when the breakdown voltage occurs and the dinistor opens. Carrying out the operation in the reverse order, that is, reducing the voltage, we should see the LED go out.

In addition to this scheme, there is a way to check using oscilloscope .

The test circuit will consist of a resistor, a capacitor and a dinistor, the connection of which will be parallel to the capacitor. We connect the power to 70 volts. Resistor – 100 kOhm. The circuit works as follows - the capacitor is charged to the breakdown voltage and abruptly discharged through db3. Afterwards the process is repeated. On the oscilloscope screen we will detect relaxation oscillations in the form of lines.

Analogs db 3

Despite the rarity of device failure, sometimes it happens and it is necessary to look for a replacement. The following are offered as analogues with which our device can be replaced: types of dinistors:

• HT-32
• Domestic KN102A

As we can see, there are very few analogues of the device, but it can be replaced with some field-effect transistors using special switching circuits, for example, STB120NF10T4.

is a bidirectional trigger uncontrolled diode, similar in design to a low-power thyristor. Its design does not have a control electrode. It has a low avalanche breakdown voltage, up to 30 V. The dinistor can be considered the most important element intended for automatic switching devices, for relaxation oscillation generator circuits and for signal conversion.

Dinistors are manufactured for maximum current circuits up to 2 A continuous and up to 10 A for operation in pulse mode for voltages from 10 to 200 V.

Rice. No. 1. Diffusion silicon dinistor p — n — p — n (diode) brand KN102 (2N102). The device is used in pulse circuits and performs switching actions. The design is made of metal glass and has flexible leads.

The principle of operation of the dinistor

Direct connection of the dinistor from the power source leads to a direct bias of the pnp junction P1 and P3. P2 works in the opposite direction, accordingly the state of the dinistor is considered closed, and the voltage drop occurs at the transition P2.

The magnitude of the current is determined by the leakage current and is within the limits of hundredths of microA (section OA). With a gradual increase in voltage, the current will increase slowly; when the voltage reaches a switching value close to the value of the breakdown voltage of the p-n junction P2, then its current increases sharply, and accordingly the voltage drops.

The position of the device is open, its working component passes into the BV region. The differential resistance of the device in this area has a positive value and lies within small limits from 0.001 Ohm to several units of resistance (Ohm).

To turn off the dinistor, it is necessary to reduce the current value to the holding current value. If reverse voltage is applied to the device, transition P2 opens, transition P1 and P3 are closed.

Rice. No. 2. (a) Structure of the dinistor; (b) CVC

Scope of application of the dinistor

1. The dinistor can be used to generate a pulse intended for unlocking a thyristor; due to its simple design and low cost, the dinistor is considered an ideal element for use in a thyristor power regulator or pulse generator circuit
2. Another common application of a dinistor is the use in the design of high-frequency converters for working with a 220V electrical network to power incandescent lamps, and compact fluorescent lamps (CFLs) in the form of a component included in the “electronic transformer” device. This is the so-called DB3 or symmetrical dinistor . This dinistor is characterized by a spread of breakdown voltage. The device is used for conventional and surface mounting.

Reversible power dinistors

A variety of dinistors with reverse-pulse properties has become widespread. These devices allow microsecond switching of hundreds and even millions of amperes.

Reverse-pulse dinistors (RPDs) are used in the design of solid-state switches to power power plants, RVDs and operate in the microsecond and submillisecond ranges. They switch pulse currents up to 500 kA in unipolar pulse generator circuits in multiple frequency mode.

Rice. No. 3. Marking of RVD used in monopulse mode.

Appearance of keys assembled on the basis of RVD

Rice. No. 4. Design of a frameless hose.

RSI.No.5. The design of the high-pressure motor is in a metal-ceramic pellet sealed housing.

The number of RVDs depends on the voltage value for the operating mode of the switch; if the switch is designed for a voltage of 25 kVdc, then their number is 15 pieces. The design of the switch based on the RVD is similar to the design of a high-voltage assembly with thyristors connected in series with a tablet device and a cooler. Both the device and the cooler are selected based on the operating mode specified by the user.

Structure of the power RVD crystal

The semiconductor structure of a reversible-switched dinistor includes several thousand thyristor and transistor sections with a common collector.

The device is turned on after changing the polarity of the external voltage for a short time and passing a short pulse current through the transistor sections. Electron-hole plasma is injected into the n-base, and a thin plasma layer is created along the plane of the entire collector. The saturable reactor L serves to separate the power and control parts of the circuit; after a fraction of a microsecond, the reactor is saturated and a voltage of primary polarity comes to the device. The external field pulls holes from the plasma layer into the p-base, which leads to the injection of electrons, and the device switches over its entire surface, independent of the area size. It is thanks to this that it is possible to switch large currents with a high rate of rise.

Rice. No. 6. Semiconductor structure of RVD.

Rice. No. 7. Typical switching waveform.

Prospects for using RVD

Modern versions of dinistors manufactured in currently available silicon diameters allow switching currents of up to 1 mA. Elements based on silicon carbide are characterized by: high electron velocity saturation, avalanche breakdown field strength with a high value, and tripled thermal conductivity.

Their operating temperature is much higher due to the wide zone, twice the radiation resistance - these are all the main advantages of silicon dinisters. These parameters make it possible to improve the quality of the characteristics of all power electronic devices made on their basis.

Write comments, additions to the article, maybe I missed something. Take a look at, I will be glad if you find anything else useful on mine.

A dinistor is a type of semiconductor diodes belonging to the class of thyristors. The dinistor consists of four regions of different conductivity and has three p-n junctions. In electronics, it has found rather limited use; however, it can be found in the designs of energy-saving lamps with E14 and E27 sockets, where it is used in starting circuits. In addition, it is found in the ballasts of fluorescent lamps.

The conventional graphic designation of a dinistor in the diagram is a bit like a semiconductor diode, with one difference. It has a perpendicular line, which symbolizes the base area, and gives the dinistor its extraordinary parameters and characteristics.

But strange as it may seem, the image of the dinistor on a number of circuits can be different. Let's say the image of a symmetrical dinistor can be like this:

This variation in graphical notations is due to the fact that there is a huge class of thyristor semiconductors. These include dinistor, triac, and triac. In the diagrams they are all similar in the form of a combination of two diodes and additional lines. In foreign sources, this subclass of semiconductor is called trigger diode, diac. On circuit diagrams it can be designated by the Latin symbols VD, VS, V and D.

The basic principle of operation of a dinistor is based on the fact that when connected directly, it will not pass electric current until the voltage at its terminals reaches a specified value.

A conventional diode also has such a parameter as the opening voltage, but for it it is only a couple of hundred millivolts. When connected directly, a conventional diode opens as soon as a small voltage level is applied to its terminals.

To clearly understand the principle of operation, you need to look at the current-voltage characteristic; it allows you to clearly see how this semiconductor device works.

Let's consider the current-voltage characteristic of the most common symmetrical dinistor type DB3. It can be mounted in any circuit without observing the pinout. It will work accurately, but the turn-on (breakdown) voltage may differ slightly, by about three volts

As we can see the wallpaper branches characteristics are absolutely the same. (indicates that it is symmetrical) Therefore, the operation of DB3 does not depend on the polarity of the voltage at its terminals.

The current-voltage characteristic has three regions showing the operating mode of a DB-3 type semiconductor under certain factors.

The blue area shows the initial closed state. No current flows through it. In this case, the voltage level applied to the terminals is lower than the turn-on voltage level V BO – Breakover voltage.
The yellow section is the moment the dinistor opens when the voltage at its contacts reaches the turn-on voltage level ( VBO or U on.). In this case, the semiconductor begins to open and electric current passes through it. Then the process stabilizes and it moves to the next state.
The purple section of the current-voltage characteristic shows the open state. In this case, the current flowing through the device is limited only by the maximum current Imax, which can be found in the reference book. The voltage drop across the open trigger diode is small and amounts to about 1 - 2 volts.

Thus, the graph clearly shows that the dinistor in its operation is similar to a diode with one big “BUT”. If its breakdown voltage of a conventional diode is (150 - 500 mV), then to open the trigger diode it is necessary to apply a voltage of a couple of tens of volts to its terminals. So for the DB3 device the switching voltage is 32 volts.

To completely close the dinistor, it is necessary to reduce the current level to a value below the holding current. In the case of an asymmetrical version, when turned back on, it does not pass current until the reverse voltage reaches a critical level and it burns out. In amateur radio homemade products, the dinistor can be used in stroboscopes, switches and power regulators and many other devices.

The basis of the design is the relaxation generator on VS1. The input voltage is rectified by diode VD1 and supplied through resistance R1 to trimmer R2. From its engine, part of the voltage flows to capacitance C1, thereby charging it. If the input voltage is not higher than normal, the capacitor charging voltage is not enough for breakdown, and VS1 is closed. If the mains voltage level increases, the charge on the capacitor also increases and breaks through VS1. C1 is discharged through the VS1 headphone BF1 and the LED, thereby signaling a dangerous level of mains voltage. After this, VS1 closes and the container begins to accumulate charge again. In the second version of the circuit, the tuning resistance R2 must have a power of at least 1 W, and the resistor R6 must have a power of at least 0.25 W. The adjustment of this circuit consists of setting the lower and upper limits of the deviation of the mains voltage level with tuning resistances R2 and R6.

The widely used bidirectional symmetrical dinistor DB3 is used here. If FU1 is intact, then the dinistor is short-circuited by diodes VD1 and VD2 during the positive half-cycle of the 220V mains voltage. LED VD4 and resistance R1 bypass capacitance C1. The LED is on. The current through it is determined by the nominal resistance R2.

Among the huge number of various semiconductor devices, there is a dinistor.

In electronic equipment, a dinistor is quite rare; it can be found on printed circuit boards of widespread energy-saving lamps intended for installation in the base of a regular lamp. In them it is used in the starting circuit. In low-power lamps it may not be present.

The dinistor can also be found in electronic ballasts designed for fluorescent lamps.

The dinistor belongs to a fairly large class of thyristors.

Conventional graphic designation of a dinistor in the diagrams.

First, let’s find out how a dinistor is indicated on circuit diagrams. The conventional graphic designation of a dinistor is similar to the image of a diode, with one exception. The dinistor has another perpendicular feature, which, apparently, symbolizes the base area, which gives the dinistor its properties.

Conventional graphic designation of a dinistor in the diagrams

It is also worth noting the fact that the image of the dinistor on the diagram may be different. So, for example, the image of a symmetrical dinistor in the diagram may be as shown in the figure.

Possible designation of a symmetrical dinistor in the diagram

As we can see, there is not yet any clear standard in the designation of a dinistor in the diagram. Most likely, this is due to the fact that there is a huge class of devices called thyristors. Thyristors include dinistor, thyristor (triac), triac, symmetrical dinistor. In the diagrams, they are all depicted in a similar way as a combination of two diodes and additional lines indicating either the third terminal (trinistor) or the base region (dinistor).

In foreign technical descriptions and diagrams, a dinistor may be called trigger diode, diac (symmetrical dinistor). Indicated on circuit diagrams by the letters VD, VS, V and D.

What is the difference between a dinistor and a semiconductor diode?

Firstly, it is worth noting that the dinistor has three (! ) p-n junctions. Let us recall that a semiconductor diode has only one p-n junction. The presence of three p-n junctions in a dinistor gives the dinistor a number of special properties.

The principle of operation of the dinistor.

The essence of the dinistor’s operation is that when connected directly, it does not pass current until the voltage at its terminals reaches a certain value. The value of this voltage has a certain value and cannot be changed. This is due to the fact that the dinistor is an uncontrolled thyristor - it does not have a third, control, output.

It is known that a conventional semiconductor diode also has an opening voltage, but it is several hundred millivolts (500 millivolts for silicon and 150 for germanium). When a semiconductor diode is directly connected, it opens when even a small voltage is applied to its terminals.

To understand in detail and clearly the principle of operation of a dinistor, let us turn to its current-voltage characteristic (volt-ampere characteristic). The good thing about the current-voltage characteristic is that it allows you to clearly see how a semiconductor device works.

In the figure below, the current-voltage characteristic (eng. Current-voltage characteristics) imported DB3 dinistor. Note that this dinistor is symmetrical and can be soldered into the circuit without observing the pinout. It will work in any case, but the switch-on (breakdown) voltage may differ slightly (up to 3 volts).

Current-voltage characteristic of a symmetrical dinistor

The current-voltage characteristic of the DB3 dinistor clearly shows that it is symmetrical. Both branches of the characteristic, upper and lower, are the same. This indicates that the operation of the DB3 dinistor does not depend on the polarity of the applied voltage.

The graph has three areas, each of which shows the operating mode of the dinistor under certain conditions.

The red section on the graph shows the closed state of the dinistor. No current flows through it. In this case, the voltage applied to the electrodes of the dinistor is less than the turn-on voltage V BO – Breakover voltage.

The blue section shows the moment the dinistor opens after the voltage at its terminals has reached the turn-on voltage (V BO or U on). At the same time, the dinistor begins to open and current begins to flow through it. Then the process stabilizes and the dinistor goes to the next state.

The green area shows the open state of the dinistor. In this case, the current that flows through the dinistor is limited only by the maximum current I max, which is indicated in the description for a specific type of dinistor. The voltage drop across an open dinistor is small and fluctuates around 1 - 2 volts.

It turns out that the dinistor in its operation is similar to a conventional semiconductor diode with one exception. If the breakdown voltage or, in other words, the opening voltage for a conventional diode is less than a volt (150 - 500 mV), then in order to open the dinistor it is necessary to apply a switch-on voltage to its terminals, which amounts to tens of volts. So for an imported DB3 dinistor, the typical turn-on voltage (V BO) is 32 volts.

To completely close the dinistor, it is necessary to reduce the current through it to a value less than the holding current. At the same time, the dinistor turns off and goes into the closed state.

If the dinistor is asymmetrical, then when turned on in reverse (“+” to the cathode, and “-” to the anode), it behaves like a diode and does not pass current until the reverse voltage reaches the critical value for this type of dinistor and it burns out. For symmetrical ones, as already mentioned, the polarity of inclusion in the circuit does not matter. It will work anyway.

In amateur radio designs, the dinistor can be used in stroboscopes, high-power load switches, power regulators and many other useful devices.