Among electrical devices designed to convert electrical energy, transformers are the most well-known and widespread structural element. Power models are used in electrical networks of various voltages, and low-power models are used in control and switching circuits, as well as in low-current networks and for connecting various electronic equipment. A step-down transformer 220 to 12 Volts - what it is needed for, and how the different types work, how to connect and check, and how to make it yourself - this is the topic of this HomeMyHome.ru article.
The appearance of a step-down transformer in the classical sense of such equipment
Why do you need a step-down transformer from 220 to 12 Volts?
The main purpose of a step-down transformer is to convert a primary voltage of 220 Volts into a secondary voltage of 12 Volts, which is used for:
- connecting light sources operating at 12 Volts (LED lamps and strips, incandescent lamps and halogen light sources, as well as other lighting devices);
- creating an electrical network in premises where, according to safety rules, it is impossible to use the voltage of a household electrical network (220/380 Volts);
- connecting low-current systems (video surveillance, alarm, etc.) operating at low DC voltage.
Appearance of the model designed for connecting LED light sources
Types of transformers
Today, spot lighting is very popular when decorating houses, apartments and offices. In this case, transformers should also be used for lamps and chandeliers, since they convert alternating current from one voltage to another, thereby ensuring stable operation of light sources. These devices are divided into winding and electronic - the latter contribute to the change in electricity using special components. Such products are characterized by lightness and compactness, and also prevent short circuits.
How to choose a transformer for lamps and chandeliers
When choosing a transformer, you must consider the following parameters:
- Device efficiency. This indicator should always tend to one.
- Temperature limits.
- Power level.
- Moisture and dust resistance class.
The geometric dimensions of the structure also play an important role when purchasing. In some cases, it is much easier to divide the light sources into groups and connect each of them to a separate product. If one of them fails, the others will continue to work, providing stable lighting for the entire room.
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Classification and types
Step-down transformers are classified according to several parameters:
- by design - electromagnetic and pulsed;
- according to technical characteristics - electrical power, the maximum permissible for connecting the load;
- by type of execution - open or placed in a protective housing;
- by type of use - household and industrial.
The most noticeable difference that determines the possibilities of using and applying 220/12 Volt step-down transformers is their design.
Model of a step-down transformer for domestic and industrial use, placed in a protective housing
Toroidal (electromagnetic) models
A toroidal (electromagnetic) transformer 220 to 12 Volts is a classic version of such devices. The design of electromagnetic models consists of a core made of special types of steel, on which the primary and secondary windings are wound. The transformation of electrical energy occurs due to the electromagnetic force generated in the body of the core.
The advantages of the design are:
- reliability;
- a variety of models with different technical characteristics and types of execution;
- relatively low cost.
The disadvantages include:
- heavy weight;
- sensitivity to voltage surges in the power supply network.
Model of an electromagnetic transformer intended for domestic use
Electronic (pulse) models
Pulse models are assembled from electronic components, which significantly expands the capabilities of step-down transformers of this type.
The advantages of electronic devices are:
- small overall dimensions and light weight;
- resistance to voltage surges in the supply network;
- stability of voltage values at the device output;
- smooth start when turned on and high power factor.
The basis of this type of design is a ferrite core with an electrical winding made on it, as well as transistors, diodes and other electronic components.
Design of an electronic step-down transformer 220/12 Volt
Why do you need a voltage transformer?
A voltage transformer is a universal device. Transmits and distributes energy.
Used in:
What kind of lighting do you prefer?
Built-in Chandelier
- electrical installations;
- power supplies;
- power transmission units;
- signal processing devices;
- power supplies of devices.
A high voltage power transformer is used for:
- supplying energy to the electrical grid at power plants;
- increasing the voltage of the generator, power lines;
- reducing voltage to consumer level.
A three-phase device with a special cooling system is used in electrical networks. The core in the composition is common to all 3 phases.
The scope of application of the network transformer is power supplies, components of electrical appliances with different voltages. Pulse units are indispensable for radio engineering and electronic devices. First, the alternating voltage in the power supplies is rectified. Next, due to the inverter, high-frequency pulses are converted, stabilizing the constant voltage.
Transformers are included in many power circuits to ensure minimal levels of high-frequency interference. For example, separation devices prevent the risk of electric shock to humans. After all, connecting household appliances to the network through a transformer becomes safe.
The second circuit of the device will be isolated from contacts with the ground, unless, of course, we are talking about grounding electrical equipment. Power measuring instruments are used in alternating current generator circuits. The number of phases of the generator from the transformer must match to achieve a stable output voltage.
Matching transformers are indispensable for electronic devices with high input impedance and high-frequency lines, but with different load impedances.
Design and principle of operation
Electronic and electromagnetic models of transformers differ both in their design and in their operating principle, so they should be considered separately:
- Electromagnetic transformer.
As already written above, the basis of this design is a toroidal core made of electrical steel, on which the primary and secondary windings are wound. There is no electrical contact between the windings; the connection between them is carried out through an electromagnetic field, the action of which is due to the phenomenon of electromagnetic induction. The diagram of a step-down electromagnetic transformer is shown in the figure below, where:
- the primary winding is connected to a 220 Volt network (U1 in the diagram) and electric current “i1” flows in it;
- when voltage is applied to the primary winding, an electromotive force (EMF) is generated in the core;
- The EMF creates a potential difference on the secondary winding (U2 in the diagram) and, as a consequence, the presence of electric current “i2” with a connected load (Zn in the diagram).
Electronic and circuit diagram of a toroidal transformer
The specified voltage value on the secondary winding is created by winding a certain number of turns of wire around the core of the device.
- Electronic transformer.
The design of such models provides for the presence of electronic components through which voltage conversion is carried out. In the diagram below, the mains voltage is applied to the input of the device (INPUT), after which it is converted into constant voltage through a diode bridge, at which the electronic components of the device operate.
The control transformer is wound on a ferrite ring (windings I, II and III), and it is its windings that control the operation of the transistors and also provide communication with the output transformer, which supplies the converted voltage to the output of the device (OUTPUT). In addition, the circuit contains capacitors that provide the required shape of the output voltage signal.
Schematic diagram of an electronic transformer 220 to 12 Volts
The above electronic transformer circuit can be used to connect halogen lamps and other light sources operating at 12 Volts.
Design and principle of operation
The device of all types (with the exception of electronic transformers) is not much different. The main working elements of step-down devices are magnetic circuits and coils. Differences are observed in the configuration of the cores and in the methods of connecting the windings.
Rice. 1. Schematic representation of a step-down device
The manufacturer selects the geometric shapes of ferromagnets based on the feasibility of production. The type of scaffold does not significantly affect the transformation. The current conversion criteria depend more on the composition of the ferromagnet and the parameters of the windings.
The magnetic system of a step-down transformer can have different shapes, determined by the way the rods are arranged:
- flat;
- spatial;
- symmetrical shape;
- asymmetrical.
Let us briefly recall the operating principle of step-down transformers.
The alternating current entering the primary coil excites electromagnetic induction. The alternating electromagnetic field spreads throughout the entire magnetic circuit. In the secondary coil, an EMF is excited by the forces of alternating magnetic fields.
The magnitude of the electromotive force (and therefore the potential difference between the coils) is determined by the ratio: U2/U1 = W2/W1 = k, where U is the voltage, and W is the number of turns. The transformation ratio k ranges from 0 to 1. The closer to zero the value of k is, the lower the value of the output voltages. The core configuration does not affect the operation of the transformer.
Finally, we note that a step-down device can be easily converted into a step-up transformer. To do this, it is enough to change the method of connecting the step-down device: swap the primary and secondary coils. Of course, you cannot connect a secondary coil designed for 12 V to a 220 V network.
Main technical characteristics
Technical characteristics determine the possibilities of using a step-down transformer, as well as the conditions of its operation, which is expressed in the following indicators:
- rated primary voltage;
- rated power;
- mode and conditions of use;
- degree of protection according to GOST 14254-96;
- housing material (if any).
Step-down transformers of the OSM1 brand of various rated power
How to choose a transformer for a chandelier
A chandelier is a type of pendant lamp, the design of which provides for the installation of several light sources (lamps). If previously there were only incandescent lamps as light sources installed in chandeliers, then the question of choosing a step-down transformer for such lighting products did not arise at all. Today, due to the introduction of energy-saving technologies, chandeliers equipped with energy-efficient light sources are becoming increasingly common. In this case, the question of choosing a transformer becomes very relevant.
Ceiling chandelier with halogen light sources
When choosing a step-down transformer designed for connecting halogen or LED lamps, you should pay attention to:
- rated voltage for which the installed light sources are designed;
- the power of all installed lamps intended for placement in one luminaire must correspond to the rated power of the transformer.
In addition, when choosing a voltage converter, you need to pay attention to its weight and overall dimensions, which allow you to place the device in the body of a lamp (chandelier).
How to connect a step-down transformer
Connecting such equipment should not be a problem, even for a person who is very far from electrical engineering. The reason for this is the marking applied to the body of the step-down transformer and indicating which terminals should be connected to the wires from the power supply network, and which to which the load should be connected. The phase wire is connected to the “L” or “220” terminal, and the neutral wire is connected to “N” or “0”, which depends on the type of marking chosen by the manufacturer.
Marking of the terminals of the primary and secondary windings on an electronic type step-down transformer intended for connecting light sources
How to test a step-down transformer
In order to check the serviceability and functionality of the step-down transformer, you will need a multimeter (tester) - a combined electrical measuring device. If there is no marking on the transformer, then the ends of both windings are initially determined. To do this, the tester probes are applied to the output terminals (wires) of the device being tested, while the multimeter is used in resistance measurement mode. When the ends of the windings are marked, it is determined which is the primary and which is the secondary. To do this, the resistance values in the windings are studied; in the primary it will be greater, in the secondary it will be less.
Using a Multimeter to Check the Functionality of a Voltage Transformer
If there are more windings, the work is performed in a similar way, with the only difference being that it becomes necessary to test a larger number of terminals. To check the functionality, voltage is applied to the primary winding, and a load in the form of a light source of the appropriate voltage class is connected to the secondary winding.
Related article:
In this publication, we will look at how to use a multimeter correctly , how the device works, how it works, what types there are, and recommendations from experts.
Ideal Transformer Equations
In such a transformer, power lines pass through all branches of the primary and secondary windings. This means that there are no vortex flows and energy losses. The magnetic field changes, but generates an identical EMF in all turns, and therefore becomes directly proportional to their total number.
When energy comes from the primary circuit, it is transformed into a magnetic field and then enters the secondary circuit.
The formula for the ideal transformer equation is P1 = I1 • U1 = P2 = I2 • U2:
- R1 – coefficient of incoming power from the first circuit to the transformer;
- R2 is the coefficient of converted power entering the secondary circuit.
If you increase the voltage at the ends of the secondary winding, the current level of the primary circuit will decrease. According to the equation - U2/U1 = N2/N1 = I1/I2, converting the resistance of one circuit to the resistance of another is possible only by multiplying the value by the square of the ratio.
Making a step-down transformer from 220 to 12 Volts with your own hands
Currently, you can find on sale any step-down transformer that meets all the requirements for this type of technical device. However, for people who have a creative streak and want to make everything with their own hands, it is quite possible to assemble a step-down transformer with their own hands. All work on the independent production of such a product can be divided into several stages: preparatory, execution of work and testing of functionality.
The choice of design and assembled circuit depends on the skills and capabilities of the performer
Preparatory stage
At this stage you should:
- decide on the type of device to be assembled - electromagnetic or electronic;
- determine the technical parameters necessary for further use - power and installation location, permissible overall dimensions and weight;
- calculate the parameters of the primary and secondary windings, in the case of manufacturing an electromagnetic model;
- purchase the necessary materials and components.
When making an electronic device, soldering iron skills and basic knowledge in the field of electronics are required. In this case, the device circuit is initially selected, and, accordingly, electronic components (transistors, capacitors, etc.) are prepared for it. In the case of manufacturing an electromagnetic model, you will first need to calculate the windings of the assembled device, and then perform all other operations.
Design of the simplest electromagnetic transformer
To determine the number of turns N1 in the primary winding, you must use the formula:
N1 = (40 – 60) / S , where
- S – cross-section of the magnetic circuit (core) of the transformer, measured in cm2;
- 40–60 is an indicator (constant) that determines the type and quality of the core.
The cross-section of the core is determined based on the geometric dimensions of the blanks used: window, width and thickness of the core jaws. The cross-section of the wire in the primary winding must correspond to the current that will flow in it during operation, which is determined by the size of the connected load, in numerical terms this is defined as:
I1 = P/U , where
- I1 – current flowing in the primary winding;
- P – power of the connected load;
- U – voltage on the primary winding.
Accordingly, knowing the amount of current flowing through the wires, you can select their permissible cross-section, in accordance with the requirements regulated by the Electrical Installation Rules (PUE). The wire cross-section for the secondary winding is determined in a similar way.
When manufactured independently, the core can be selected in various shapes and designs
The number of turns in each winding is determined by the formula:
W = U × (V / 10) where
- W – number of turns in the winding;
- U – voltage in the transformer winding;
- V – frequency of electric current – 50 Hz.
Having decided on the number of turns, and therefore the dimensions of the core, as well as the required length and cross-section of the wire in both windings, you can prepare the necessary materials to complete the work:
- wire for both windings;
- core - you can purchase a new one or use it from used equipment (TV, radio, etc.);
- insulating materials (tape, paper and others).
In addition, it is possible to make a winding machine that facilitates the production of windings, in the case of the option when the windings are made in the form of coils placed on the core.
Execution of work
When all preparatory activities have been completed, you can begin manufacturing and assembling the transformer, in this case the work is performed as follows:
| Illustration | Description of action |
| The coil frames are made from electrical cardboard or other material. | |
| Using a winding machine or manually, wire is wound onto coils; the number of turns on each coil must correspond to the values determined by calculation for each winding. | |
| The coils are placed on the prepared core, their ends are fixed and marked accordingly. |
Functionality check
When the transformer is assembled and all its components are securely fastened and insulated, it is necessary to check its functionality. To do this, a voltage of 220 Volts is supplied to the primary winding, and a load designed to operate at a voltage of 12 Volts is connected to the secondary winding.
If the test is successful, the assembled product is placed in the prepared housing or installed in the location intended for placement.
How much does it cost and where to buy a 220/12 Volt step-down transformer - price review
The price of 220 to 12 Volt transformers depends on their technical characteristics, purpose and degree of protection, as well as the place of their sale. These products can be purchased in lighting and electrical stores, retail chains of various equipment and building materials, as well as on the Internet.
In the departments of lighting and electrical products, step-down transformers of various brands and designs are always on sale
The following table shows the cost of various models of step-down transformers when selling them through Internet resources, as of the second quarter of 2022.
| Model | Specifications | Average cost (as of May 2022), rubles |
| TDM SQ0360-0011 | Electromagnetic 220/12V 35−105W | 529 |
| TDM SQ0360-0010 | Electromagnetic 220/12V 20−60W | 389 |
| YaTP-0.25 | Electromagnetic 0.25 kW, 220/12V, IP30 | 1500 |
| GALS ET-190K | Electronic 220/12V 105W | 550 |
| GALS ET-190T | Electronic 220/12V 250W | 1469 |
| SVETOZAR SV-44955 | Electronic 220/12V, 1 input−2 outputs | 215 |
| SVETOZAR SV-44965 | Electronic 220/12V 2 inputs-3 outputs | 649 |
| NT-EH-060-EN Navigator | Electronic 220−12V 60W | 200 |
| NT-EH-105-EN Navigator | Electronic 220−12V 105W | 270 |
transformer TDM SQ0360-0010
YaTP-0.25
GALS ET-190K
GALS ET-190T
NT-EH-060-EN Navigator
NT-EH-105-EN Navigator
The presence of various models that differ in technical characteristics, sizes and operating conditions allows you to select a step-down transformer in accordance with the requirements for it in different price ranges.
Nowadays, it is not difficult to buy a voltage converter; the main thing is to make the right choice from the variety of offers on the electrical products market
Transformers 220-110
In many countries of the world, for example in the USA and other countries of North and Central America, the standard power supply voltage is not 220 Volts, like ours, but only 110-120. It is clear that their electrical appliances cannot be directly connected to our network. However, if our devices are connected to their network, nothing good will come of it either. Here you need a 220-110 transformer
, which will change the voltage to the desired value.
In the USA, the nominal network voltage is 120 Volts at a frequency of 60 Hz. Our network has a frequency of 50 Hz, and to power American equipment at this frequency the optimal voltage will be not 120, but 110 Volts, especially for electrical appliances containing electric motors, power transformers and other inductive elements operating on mains voltage. For devices containing switching power supplies, such a reduction in voltage is not at all critical; they feel great at both 100 and 130 Volts. Therefore, it is common practice to use 220-110 converters to power American equipment, which reduce the voltage from 220 to 110 Volts. Through the same 220-110 transformers, switched on in reverse, we can power our electrical appliances from a 110-120 Volt network. Some Chinese manufacturers specialize in the production of such 220-110 transformers. Among the many Chinese brands, it is worth highlighting such companies as ELECA, JOHSUN, DAYTON. The best of the Chinese 220-110 converters are JOHSUN transformers
, next are
ELECA transformers
and then
DAYTON transformers
.
All Chinese-made 220-110 transformers are quite cheap, thanks to the use of prefabricated cores made of stamped plates and aluminum windings. But such cores produce a characteristic sound during operation, and there are more losses in aluminum windings than in copper ones. Therefore, we advise you to opt for TOROID transformers
made in Poland.
These 220-110 transformers are assembled on a ring-shaped core made of high-quality transformer steel. The windings of these transformers are copper with high-strength insulation. TOROID transformers
are manufactured as two-winding (isolating) and single-winding (
autotransformers
).
220-110 isolating transformers
are preferred in applications where increased safety requirements are present, and in most cases the cheaper and lighter
220-110 autotransformers
.
The TOROID transformer range covers a power range from 50 to 8000 VA. TOROID converters
are very easy to use; the device is housed in a nice plastic (models up to 300VA) or metal case, on which American standard sockets are installed, so
you don’t need adapter for the socket Impeccable quality and time-tested reliability are TOROID transformers.
