How to make the power supply with their own hands 12: diagram and instructions

Power supply units differ in design, technical specifications and other purposes.

CONTENT

1 Types of power supplies, their basic specifications
2 Application area
3 Schematic diagram and principle of operation
4 Calculation of the power supply capacity by 12 V
5 Diodes for Power Supply
6 voltage regulation
7 Switching power supply 12 V with his own hands - scheme
8 The main stages of the manufacture of switching power supply 12 with their hands
9 Nuances of manufacturing the power supply for the screwdriver
10 Where to buy and how much is 12 V power supply unit
11 Video: power supply screwdriver to 12c from the computer power supply.

Types of power supplies, their basic specifications

The power supply unit is a secondary energy source for technical devices, transforming the mains voltage supply at their operating voltage.

The most popular are the power supply units whose primary voltage - is an alternating voltage Household electrical network, equal to 220 volts, and the secondary - converted in a constant equal to 24/12/5 / 3.3 V. On the principle of converting voltage power supply units (PSU) are divided into two types:

transformer - when the conversion is performed by a step-down transformer, they are called linear;
Switching - the conversion is carried out thanks to the electronic components, providing voltage conversion, they are called the inverter.

If the BP circuit provides an output voltage stabilizer, such a device is called a stabilized power supply unit.

The main technical characteristics of determining the possibility of the use of such technical devices are:

electric power, measured in watts (W × A or B);
voltage at input and output, measured in volts (V);
output current measured in amperes (A);
efficiency - a useful parameter when using high-power PD is measured in%;
presence of security elements the internal electric circuits from overload and short circuit currents.

Application area

Power supplies secondary voltage of 12 volt pulse type used to connect to the home electric network:

personal computers of different types - to recharge their batteries and work directly from the network;

for charging electronic gadgetsIncluding cell phones and smart phones, music players and video cameras, and other devices, having in its design batteries;
for manual charging of the portable electric tool - screwdriver, Bulgarian, etc .;
to connect the LED lighting devices (LED lamps and tapes);
for other devicesInvolving the work of network of DC 12 V and up to 5 amperes - avtopriomnik radio or in a home or garage.

Schematic diagram and principle of operation

Schematic diagram and principle of operation depends on the type of device, and therefore it is necessary to consider them separately:

Transformer PSU.

Analog type BP in its circuit has a step-down transformer providing the secondary voltage value in predetermined quantities, and a diode bridge which serves for its rectification. The simplest scheme of such a device is as follows:

Schematic diagram of the analog power supply

Capacitors installed in the circuit provide smoothing voltage pulse at the output of the power supply.

~~Transformer power supply~~

Switching mode power supply.

Inverter type of power supply operates at the expense of the electronic components of the device circuit. Supply voltage is applied to the input diode bridge, and its peaks are smoothed by capacitors installed. Thereafter, the signal is converted in the other circuit elements (transistors, integrated circuit, thyristors, etc.) and is fed to the pulse transformer.

Transformers of this type are made on the basis of ferromagnetnyh materials, so a small package, allowing to minimize the size of the PSU. Voltage obtained after transformation, is supplied to the load (the power supply output). This type of power supply circuit called a galvanically isolated.

Switching power supply on the integrated circuit and resistors postroechnyh

There PSU circuits without galvanic connection. In this case, the input signal is directly fed to the low pass filter.

~~Impulse power block~~

Calculation of the power supply capacity by 12 V

Power PD is one of the main technical characteristics determine the possibility of connecting a varying load. Power can therefore be calculated in different ways:

For LED strips.

In this case, the calculation is as follows:

It is taken as a basis for power in 1 meter LED-tape, indicated by the manufacturer on the packaging;
It is defined by its length;
These values are multiplied, and the resulting expression is increased by 30%.

An increase of 30% provides the necessary power reserve. This calculation can be expressed by the following formula:

Pblock = Pbeats × Ltape × KstockWhere:

Pblock- electric power supply unit;

Pbeats- an electric power of 1 meter LED strip;

Ltape - the length of the tape;

Kstock - power headroom factor.

For a personal computer.

If necessary, determine the PD power of a personal computer should be aware of all the elements of power devices in its kit. This is no easy task, so there are special programs and online calculators that perform this calculation. Here are some of them:

OuterVision® - calculator, download link: https://outervision.com/power-supply-calculator
Company «Enermax», Power Calculator - download link: http://www.enermax.outervision.com/index.jsp
MSI - power supply calculator download link: https://ru.msi.com/power-supply-calculator
KSA Power Supply Calculator WorkStation - Download link: http://ksa-soft.ru/soft/10-ksa-power-supply-calculator-workstation.html

For charging electric tools and electronic gadgets.

When it is necessary to determine the charging power supply power screwdriver, the smartphone or other electronic device, it is necessary to know their electrical power and to take into account a safety factor. This can be reflected by the following formula:

Pblock = Pdevices × Kstock

Diodes for Power Supply

For rectifying an alternating voltage mains electricity supply in the power circuits and other electronic devices using diodes blocks collected in a bridge circuit. Schematically semiconductor diode as follows.

Apparatus semiconductor diode

For device 4, the diode bridge uses the same type of diode, which are connected a certain way, is shown in the following scheme. Their specifications should correspond to the value of current flowing through them, as well as the largest allowable reverse voltage.

Scheme compounds diode bridge circuit

voltage regulation

To stabilize the voltage in the power supply used electrolytic capacitors of large capacitance and stabilizer. Capacitors smoothed voltage signals that have a half-sine shape to almost a straight line. The larger the capacitance of the capacitor, the signal at the output of a regular shape, and tends to a straight line. Zener diodes provide the constancy of the output voltage power supply.

Switching power supply 12 V with his own hands - scheme

There are many different schemes of power supplies having different specifications and collected on various electronic components. Below is a diagram of a pulsed power supply with a secondary voltage of 12 volts.

Schematic diagram of the switching power supply

When independent manufacturing such devices must be remembered that for a given ripple voltage at the output capacitor capacitance should be taken at the rate of 1 microfarad at 1 W output power. Electrolytic capacitors must be designed for the voltage of at least 350 V. The optimum ratio of the power supply unit and the technical characteristics of the electronic components provided in the following table:

Power Supply	The circuit elements
power, kWt	Current A	Diode Current, A	Capacitance of the capacitor, uF
0,1	0,4	0,2	100
0,2	0,8	0,4	200
0,3	1,2	0,6	300
0,5	2	1	500
1	4	2	1 000
2	8	4	2 000
3	12	6	3 000
5	20	10	5 000

The main stages of the manufacture of switching power supply 12 with their hands

by BP fabrication work can be divided into several stages: preparation, installation, and performance testing. In this article we consider the production of the power supply scheme, is shown in Figure number 10.

Preparatory stage

During this period, power is calculated. It should be sufficient for use with a load that is planned to connect. Selectable appearance and circuit PD (see. Figure № 10), after which the necessary components are acquired. In this case it is:

PTC thermistor;
two capacitors of 1 microfarad calculation at 1 W power;
diode bridge (diodes must comply with voltage and current);
Driver - IR2152 (IR2153, IR2153D);
FETs - IRF740, IRF840;
transformer (You can use the b / y on a PC);
diodes mounted on the output, HER series.

Installation of power supply

Step by step instructions for the manufacture of pulsed power supply of the reduced above scheme is as follows:

Screenshot	The operation to perform
Draw a diagram of the printed circuit board (marked by arrow).
The printed circuit board is made for this: used foil insulator; previously drawn pattern transferred onto the board blank; etching is performed; zasverlivayutsya holes serving for fixing the circuit elements.
Installs diodes and a thermistor.
A condenser.
Installs a driver.
Mounted FETs. When fixing the radiator, using special insulating gaskets and washers.
A transformer.
Mounted LEDs "output".
All elements mounted on the board, propaivayutsya.
Schematic diagram ready.
Manufactured housing.
The circuit board is placed in the body and is fixed in it.

operability test

When BP is assembled, it is necessary to check for this:

to the output of the power supply load is connected;
PD included in the electrical network.

If the connected load is operating normally: LED-lamps emit light, gadgets and tools are charged, and the other technique works - then the installation was successful. Another method of manufacturing the power supply - is the placement of the device elements DIN rail.

DIN Rail - a profiled metal strip, intended for fixing electrical appliances and electrical circuit elements.

When using DIN rail there is no need to manufacture a circuit board, but the construction is obtained more bulk, because the connection between the circuit elements have to be carried out using connection wires.

Nuances of manufacturing the power supply for the screwdriver

At 12, the power supply manufacturer in their own hands to connect the screwdriver to the power grid following the nuances to be considered, associated with its use:

The output voltage must be 18-19 V, otherwise the capacity of the device will decrease significantly.
Electronic components power supply circuit according to the nominal current operating screwdriver.
Size assembled unit must be such as to accommodate a dismantled battery housing (in the case of manufacturing integrated structures).

In all other manufacturing steps are similar as in the case of separately placeable embodiment BP execution.

Where to buy and how much is 12 V power supply unit

They are sold in consumer electronics stores, office equipment, as well as in organizations specializing in their repair. In addition, the Internet is also a proposal of different companies offering to implement PD of various kinds.

The power supply DC-12V, 20.8A, 250W in waterproof case, the degree of protection - IP67

PSU value depends on their specifications and performance type, determining the possibility of using this device. The higher the power and the degree of protection - the greater the price. It can range from a few hundred to a few thousand. The most cheap models:

ARDV-05-12A (12V, 0,4A, 5W) - 200 rubles;
ARDV-12-12AW (12V, 1A, 12W) - 300 rubles;
ARDV-24-12A (12V, 2A, 24W) - 400 rubles.

Models in this segment:

APS-100L-12BM (12V, 8.3A, 100W) - 800 rubles;
APS-150-12BM (12V, 12.5A, 150W) - 1000 rubles;
APS-250-12BM (12V, 20.8A, 250W) - 1 400 rubles.

The large number of offers in the market of accessories for household appliances and appliances allows you to select the power supply in accordance with its requirements. And the presence of a free access of different schemes, and also allows the manufacture of electronic components Power supply with their own hands, even a novice electronics enthusiast with primary skills soldering iron.