Thyristor KU202N belongs to the group of triode devices with the structure p - n - p - n. The junctions are created by planar-diffusion of silicon. The thyristor is designed to switch high voltages using small levels through an additional output. Depending on the switching scheme, it can open or close, providing the required modes of operation of the device. It is used in interlocking, protection systems, servo drives, remotely controlled switching systems, chargers as a switch or charge current regulator.

Thyristor KU 202N can be bought in many places, because it is a fairly common component. Moreover, its price is much lower than imported analogues. It can also be found in many Soviet devices, from power supplies to switching devices.

Design

Structurally, the thyristor KU202N and the entire series are made in a metal case made of coated copper alloy, which has threaded pins and two solder pins of various thicknesses and heights. The size of the threaded outlet or anode (A) is M6 for the nut. The terminals are made rigid by pouring with epoxy resin, but during installation, forces of more than 0.98 N should not be applied.

When performing soldering of the power output (K), it is necessary to observe a minimum distance to the glass of at least 7 mm, since high temperature may damage its integrity. When connecting the control output (UE), you must maintain a distance from the glass of at least 3.5 mm for the same reason. In this case, the total holding time of the soldering iron is not recommended to exceed more than 3 s. The effective temperature of the soldering tool tip should not exceed +260 degrees.

Features of circuit connection

The thyristor is designed to switch voltage in various devices . But at the same time, there is a standard scheme for its connection, which it is highly not recommended to violate. For example, a resistor must be connected between the cathode (solder pin) and the control electrode as a shunt component. Due to its presence, the control circuit is closed and the transition is saturated. Its resistance should be no more and no less than 51 ohms.

If a voltage of negative polarity is present at the anode, then the control current should be zero. Otherwise, an electrical breakdown of the transition will occur, which will lead to a malfunction of the entire device as a whole. Its further work is impossible, as well as reverse recovery.

Thyristor KU202N belongs to the group of high-voltage devices, designed to operate at voltages up to 400 V with a maximum allowable direct current in the open state of not more than 10 A. In total, there are 12 models of thyristors in the line with different voltages in the closed state. Therefore, when choosing the main parameter is it.

For use in circuits with voltages of 300 volts and above, thyristors with letter designations from K to H are designed. As for the rest of the parameters, they remain the same. Quite often, novice radio amateurs encounter such problems, which leads to additional waste.

These thyristors are often used in the construction of power regulators with a load of no more than 2 kW. But it is highly recommended not to use it. in critical conditions. A current of no more than 7-8 A should be passed through the device, which will provide the most efficient and gentle modes.

Thyristor test

Many are interested in how to check the KU202N thyristor and how to turn it on correctly in the device to check its performance. The fact is that quite often it turns out to be faulty for various reasons. Moreover, defects are also found in new products.

You can check the thyristor in several ways:

• Use a special device that analyzes the parameters of all transitions.
• Use a megger to check the condition of the main junction in both directions. In the opposite direction, it should ring like a normal diode, in direct connection it is closed, in an ideal state, its resistance should be equal to infinity.

The second method is applicable only to a series of devices with the letter index M and H. In this case, you can set the continuity voltage up to 400 V. Devices with the letters K and L only up to 300 V, Zh and I - up to 200 V, and so on. Before checking the product in this way, it is necessary to check it specifications with reference table. Otherwise, you can damage the device without even using it for its intended purpose.

Less powerful thyristors can be checked with a conventional multimeter in continuity mode (diode icon and sound signal). In the opposite direction, it rings like a diode, in the forward direction - infinity.

Important! When testing the thyristor in diode mode, it is necessary to combine the RE with A.

Check in switching mode

To make sure the thyristor is working, enough to assemble a small wiring diagram, consisting of the following components:

1. light bulbs or LEDs with an appropriate resistor if connected to a 12V power supply;
2. a low voltage source, for example, an AA battery;
3. several conductors and a voltage source of 12 V.

To carry out the verification, perform the following steps:

1. We connect the load to the 12 V power supply and A-K thyristor circuit.
2. We apply negative voltage to the outputs of the RE and A (+ batteries must be connected to A) for a moment.

Then the lamp or LED will light up. To make it go out, it is necessary to disconnect the switched circuit or change the polarity of the control voltage. This mode is considered normal for operation and can be used at any constant switching voltages within the allowed limits. In the case of the KU202N thyristor, it should not exceed 400 V.

Analogues KU202N

Like any other devices, domestic thyristor KU202 has a foreign analogue, which by its parameters belongs to the same category of components. Foreign manufacturers long ago they left the production of such a form factor in terms of the power of thyristors in a metal case. Only elements in the TO220 transistor package will be available on the market. Therefore, in any case, it will be necessary to make structural changes to the board and the mounting location in particular.

Foreign analogues of the KU202N thyristor include devices:

• VT138;
• VT151.

The parameters differ slightly from the component described above, and the average current, among other things, is 7.5 A. You can also use the newer Russian element T112-10 in the circuits. He also has metal case with a threaded outlet, but its dimensions will be slightly smaller.

Simple control circuits KU202N

For thyristor KU202N control scheme is quite simple. The first option was described in the device verification section. It included a 1.5 V battery, a light bulb, and a 12 V power supply. But there are also many other ways to simply connect a thyristor. Consider the most a simple circuit at its base.

power regulator

The circuit implements the principle of frequency-pulse regulation of the thyristor firing angle due to synchronization with the network. Such control is the most efficient and reliable, since the thyristor operates in normal modes without overestimating its capabilities.

The circuit contains a generator, which generates control pulses and shifts them relative to the fronts of the pulses when the mains voltage passes through zero. The control sequence of pulses is applied to the RE and K. The voltage in the load is rectified using a full-wave rectifier. The use of capacitors in the circuit as filters is unacceptable, as they will violate the main principle of operation of the device. Such a power regulator can be used to control the temperature of a soldering iron tip by changing its supply voltage. But if you need to organize the control of the primary circuits of the transformer, you will have to turn on the load in front of the diode bridge. The regulation current should be no more than 7.5 A.

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First read the classification of thyristors and the list of their main reference parameters.

Type

KU201 (2U201), KU202 (2U202) with different letter indexes- non-locking, reverse-non-conducting, cathode-controlled thyristors (control voltage is applied between the control electrode and the cathode)