Simple current stabilizer: principle of operation, pulse model, universal adjustable device

To effectively overcome various interference in the network, it is necessary to use simple current stabilizers. Modern manufacturers are engaged in the industrial production of such devices, due to which each model differs in its functional and technical characteristics. In the household industry, there are no big requirements for current stabilizers, but high-quality measuring equipment always needs a stable voltage.

Short description

Experienced craftsmen are well aware that the simplest current limiters are presented in the form of ordinary resistors. Such units are often called stabilizers., which is not reality, since they are not able to remove all interference when the voltage fluctuates at their input. The use of a resistor in the power supply circuit of a device is possible only if the entire input voltage is stabilized.

In a different situation, even the smallest voltage surges are perceived as an increased load, which negatively affects the operation of the entire device. The efficiency of resistive current limiters is rather low because the energy they consume is dissipated as heat.

A higher level of efficiency is possessed by those designs that are made on the basis of ready-made integrated circuits of linear stabilizers. The circuits of such devices are distinguished by a minimum set of elements, ease of setup and the absence of interference. To avoid unwanted overheating of the control element, the differences between input and output voltages should be kept to a minimum. Otherwise, the microcircuit case will be forced to dissipate all unclaimed energy, which several times reduces the final efficiency indicator.

Circuits with pulse-width modulation have the greatest efficiency. Their production is based on the use of universal microcircuits, where there is a reverse circuit communications and special protective mechanisms, due to which the reliability of all devices. The use of a pulse transformer leads to the retention of the circuit, which positively affects the level of efficiency and the duration of the service life. It is worth noting that such stabilizers are often made by craftsmen with their own hands, using special parts for this.

Functionality

Only a master who knows well the principle of operation of a current stabilizer will be able to effectively use this device in various fields. The main difficulty is that power grids are saturated with various noises that negatively affect the performance of equipment and devices. To effectively overcome sources of negative impact, experts everywhere use voltage and current stabilizers.

Each such product contains irreplaceable element - transformer, which ensures the stable and trouble-free operation of the entire system. Even the most elementary circuit is necessarily equipped with a universal rectifier bridge, which is connected to different resistors and capacitors. The main performance characteristics include the limiting resistance level and the individual capacitance.

Qualified specialists note that a simple current stabilizer functions according to the most elementary scheme. The thing is that the electric current flows to the main transformer, due to which its limiting frequency changes. At the input, it always coincides with this indicator in the mains, being within 50 hertz. Only after the current conversion has occurred, the limiting frequency will be reduced to the optimal level.

It is worth noting that in the traditional circuit there are powerful high-voltage rectifiers that help determine the polarity of the voltage. But capacitors are involved in high-quality current stabilization, resistors eliminate existing interference.

Making a simple converter for LEDs

Experienced craftsmen will agree that it is not so difficult to assemble a high-quality and durable stabilizer. The main feature is that a whole system of low-voltage capacitors of 20 volts can be installed on the unit, and a pulse microcircuit can have an input up to 35 V. The simplest DIY LED stabilizer is the LM317 variant. You only need to correctly calculate the resistor for the LED used using a specialized online calculator.

An important fact remains that for the well-coordinated operation of such a unit improvised food is great:

• Standard 19 volt unit from a laptop.
• At 24 V.
• More powerful 32 volt unit from a conventional printer.
• Either 9 or 12 volts from some consumer electronics.

The main advantages of such a converter always include its availability, the minimum number of elements, a high degree of reliability, and availability in stores. Collecting a more complex circuit on your own is very irrational. If the master does not have the necessary experience, then it is better to buy a pulse current stabilizer ready-made. It can always be improved if necessary.

The duration of the LED operation without loss of brightness depends on the mode. The main advantage of the simplest stabilizers (drivers), such as the LM317 stabilizer microcircuit, is that they are rather difficult to burn. The LM317 connection diagram requires only two parts: the microcircuit itself, which is included in the stabilization mode, and the resistor. The assembly process itself consists of several main stages:

1. You will need to buy a variable resistor with a resistance of 0.5 kOhm (it has three leads and a knob). You can order it via the Internet or buy it from the "Radio Amateurs".
2. The wires are soldered to the middle terminal, as well as to one of the outermost ones.
3. The resistance of the resistor is measured with a multimeter in the resistance measurement mode. It is necessary to achieve a maximum reading of 500 Ohms (so that the LED does not burn out with a low resistance of the resistor).
4. After carefully checking the correctness of the connections before connecting, the circuit is assembled.

For any device, you can achieve a supply of 10 A (set by a low-resistance resistance). For these purposes, you can use the KT825 transistor or install an analogue with better technical characteristics and a cooling system. The maximum power of the LM317 is 1.5 amperes. If there is a need to increase the current, then a field-effect or conventional transistor can be added to the circuit.

Universal adjustable model

Many technicians are faced with the need to use a high-quality stabilizer that would allow a wide range of network settings. Some modern circuits differ in that they provide for the presence of a current-setting resistor with reduced characteristics. Experts themselves note that such a device allows amplifying the voltage in another resistor. This state is commonly referred to as enhanced error voltage.

The parameters of the reference and error voltage can be compared using a reference amplifier, thanks to which the wizard adjusts the state of the field-effect transistor. It should be noted that such a scheme requires additional power supply, which must be supplied to a separate connector. The thing is that the supply voltage must ensure the coordinated operation of absolutely all components of the used circuit. The permissible level should not be exceeded, as this could lead to premature equipment failure.

In order to properly adjust the operation of an adjustable current stabilizer, you must use a special slider. It is the trimming resistor that allows the master to set the maximum current value. Setting up the network turns out to be more flexible, since all parameters can be independently adjusted depending on the intensity of operation.

Multifunctional device

Drivers for 220 V LEDs have an average manufacturing complexity. Setting them up can take a long time, requiring setup experience. Such a driver can be retrieved from LED lamps, spotlights and fixtures with a faulty LED circuit. Most of them can also be modified by finding out the model of the converter controller. The parameters are usually set by one or more resistors.

The datasheet indicates the level of resistance required to obtain the desired current. If you install an adjustable resistor, then the number of Amperes will be adjustable (but without exceeding the specified nominal power).

Until recently, the XL4015 universal module was very popular. According to its characteristics, it is suitable for connecting high power LEDs (up to 100 watts). The standard version of its case is soldered to the board that acts as a heatsink. To improve the cooling of the XL4015, the circuit must be modified with a heatsink installed on the box of the unit.

Many users simply put it on top, however, the efficiency of such an installation is rather low. It is advisable to place the cooling system at the bottom of the board, opposite the soldering of the microcircuit. For optimal quality, it can be unsoldered and installed on a full-fledged radiator using thermal paste. The wires will need to be lengthened. Additional cooling can be installed for diodes, which will significantly increase the efficiency of the entire circuit.

Among the drivers, the most versatile is considered to be adjustable. A variable resistor must be installed, which sets the number of amperes. These characteristics are usually indicated in the following documents:

• In the accompanying documentation for the microcircuit.
• The datasheet.
• In the standard wiring diagram.

Without additional cooling of the microcircuit, such devices withstand 1-3 A (in accordance with the model of the pulse-width modulation controller). The main disadvantage of these drivers is excessive heating of the diode and choke. Above 3 A, cooling of a powerful diode and controller is required. The choke is replaced with a more suitable one or rewound with a thick wire.

Indispensable DC device

Even a novice master knows what such the unit works on the principle of double integration. In absolutely all models, converters are responsible for this process. Universal dual-channel transistors are designed to increase the existing dynamic characteristics. It is important to remember that large capacitors must be used to eliminate heat losses.

It is possible to make a straightening indicator only due to an accurate calculation of the required value. As practice shows, if 12 amperes are obtained with a DC output voltage, then the limit value should be 5 V. The device will be able to stably maintain an operating frequency at around 30 Hz. Regarding the threshold voltage, it all depends on the blocking of the signal that comes from the transformer. But the front of the pulses should not exceed 2 ISS.

Only high-quality current conversion can ensure the coordinated operation of the main transistors. In this circuit, only semiconductor diodes are allowed. If the resistors are ballast, then this is fraught with high heat losses. That is why the spreading coefficient is significantly increased. The master can see that the amplitude of the oscillations has increased, but the process of inductance has not occurred.

Modern circuit based on KREN

Such a device will only work stably with LM317 and KR142EN12 elements. This is because they act as universal voltage regulators, coping well with currents up to 1.5 A and output voltages up to 40 volts. In the classic thermal mode, these elements are able to qualitatively dissipate power up to 10 watts. The microcircuits themselves have low self-consumption, since this figure is only 8 mA. The main thing is that this indicator remains unchanged even if the voltage fluctuates.

Special attention should be paid to the LM317 microcircuit, which is able to maintain a constant voltage across the main resistor. This constant resistance unit ensures maximum stability of the current passing through it, which is why it is often called a current setting resistor. Modern stabilizers on KREN differ from their counterparts in relative simplicity, due to which they are actively used as a charger for batteries and for electronic loads.