Computer power supply for charging a car battery. How to make a car charger from a computer power supply. Video about assembling a charger from a computer power supply for a car battery

Old AT or ATX power supplies assembled on a TL494 PWM controller (aka: μPC494, μA494, UTC51494, KA7500, IR3M02, MV3759, etc.) with a power of 200 - 250 W are suitable. Most of them are like this! Modern ATX12B, 350 - 450 W, of course, is also not a problem to remake. Well, we will focus on 200-300 W. I took SPARKMAN 250W. General structural scheme any block looks like this:

First, you need to make sure the unit is working. To do this, connect to the network through a 220V lamp (series connection). If the lamp flashes and goes out, then this good sign. Take the PS_ON wire ( grey colour) and short to ground, if the cooler rotates, then the power supply is working. If the 220 V lamp is on, it means there is a short circuit. There are several options:
1) The diode bridge is broken.
2) The fuse has blown (if there are no signs of life at all).
3) The transistors in the semi-bridge inverter of the high-voltage part of the power supply unit are broken.

By ringing the voiced elements, we replace them with serviceable ones. So the power supply was fixed. Now you need to strengthen the elements of the high-voltage part. We change the input electrolytes to a larger capacity - 470 µF 200V. I replaced the diodes in the bridge with 1N5408, use at least 2-amp diodes.

A K73-17 type capacitor usually costs 1 µF 250 V, but was changed to 2.2 µF at 400 V.

To modify, we will need to remove all secondary rectifiers except one (although replacing almost all components in it), add a control circuit, a shunt and measuring instruments. To remove the output voltage, the 12-volt winding of the step-down transformer T1 is used. But it is more convenient to install the rectifier and filter in place of the 5-volt one - there is more space for diodes and capacitors.

1. Unsolder all elements of rectifiers and filters +5, +12 and -12 V. With the exception of damper circuits and inductor.

2. Cut the tracks leading from the 5-volt taps of the winding of transformer T1 to the +5 V rectifier diode assembly, while maintaining its connection to the –5 V rectifier diodes (we will need it later).

3. We leave the five-volt assembly on Schottky diodes; now there will be 12 Volts here, since this assembly is designed for a higher current than the 12-volt one.

4. Connect the terminals of the 12-volt winding with the installed diode assembly using thick wire jumpers. The snubber circuits connected to this winding are retained.

5. In the filter, instead of the standard ones, install electrolytic capacitors with a capacity of 1000 - 2200 µF for a voltage of at least 25 V. And also add 0.1 µF ceramic capacitors. Install a 100 Ohm load resistor with a power of 2 W instead of the standard one (I paralleled two at 200).

6. If, during the process of checking the power supply under load, the group filtering choke did not heat up, then it is enough to rewind it. Wind all the windings from it, counting the turns. If possible, wind a new winding with two wires folded together with a diameter of 1.0 - 1.3 mm (similar to a standard 5-volt one) and a number of turns of 25-27. I wound it in one wire.

7. To power the fan, a 5-volt winding is used, and the rectifier wiring is –5 V, which we convert to +12. The diodes used are standard, from a –5 V rectifier; they must be soldered with reverse polarity. The choke is no longer needed - solder the jumper. And in place of the standard filter capacitor, install a capacitor with a capacity of 470 uF 16 V, of course, with reverse polarity. Place a jumper from the filter output (formerly -5 V) to the fan connector. Directly near the connector, install a ceramic capacitor. The voltage on my fan is +11.8 V, and at low load currents it decreases.

The following circuit was used to control current and voltage.

However, I used a resistance of 0.1 Ohm as a shunt, which made it possible to run an ammeter without an op-amp or other voltage multipliers. Type and location of the voltmeter and ammeter.

This device is assembled on the ATMEGA8 MK. But you can use any, even arrow ones. The power was taken from the standby voltage of the power supply (5V on the board is marked as +5VSB lilac wire), the only thing was that a 1000uF 16V capacitor was added to smooth out the ripples. Appearance front panel and connection connectors.

You can do it yourself Charger from a regular computer power supply.

What properties will it have: the voltage for the battery will be 14 V, but the charging current will depend on the device. This charging method is provided by the car's generator in standard operating mode.

The difference between this article and other similar ones is that the assembly of the product is quite simple. You don't need to make homemade boards and fancy transistors.

Actually what we need:
1) a regular power supply from a computer is approximately 230 W, that is, a 12 V channel consumes 8 A.
2) a 12V automotive relay (with four contacts) and two diodes for a current of 1A
3) several resistors of different powers (depending on the model of the power supply itself)

After opening this power supply, the author discovered that it was based on a UC3843 chip. This chip is used as a pulse generator and for overcurrent protection. The voltage regulator on the output channels is represented by the TL431 microcircuit:

A tuning resistor was also installed there, which serves to regulate the output voltage in a certain range.

To make a charger out of this power supply, we will need to remove unnecessary parts.

We unsolder the 220\110V switch and all its wires from the board.
We don’t need it, because our power supply will always operate at 220 voltage.

Then we remove all the wires at the output, except for the bundle of black wires (there are 4 wires) - this is 0V or “common”, and the bundle of yellow wires (there are 2 wires in the bundle) - this is “+”.

Then we will make the unit work constantly when connected to the network. As a standard, it only works if the necessary wires in those bunches. It is also necessary to remove the overvoltage protection, since it turns off the unit if the voltage rises above a certain value.

The whole reason is that we need 14.4V at the output of the device and not the standard 12.

It turned out that the turn-on and protection signals operate through one optocoupler, and there are only three of them.
In order for charging to work, you will always have to close the contacts of this optocoupler with a jumper:

After this action, the power supply will operate regardless of the network voltage.

The next step is to set the output voltage to 14.4V instead of 12. To do this, we had to replace the resistor that was connected in series with the trimmer with a 2.7 kOhm resistor:

Now we have to dismantle the transistor, which is next to TL431. (why it is unknown, but it blocks the operation of the microcircuit) This transistor was located in this place:

To stabilize, we add a load to the output of the power supply in the form of a 200 Ohm 2W (14.4V) resistor and for the 5V channel a 68 Ohm resistor:

After installing these resistors, you can begin to regulate the output voltage without a load at 14.4V. To limit the output current to 8A (the permissible value for our unit), you need to increase the power of the resistor in the power transformer circuit, which is used as an overload sensor.

We install a 47 Ohm 1 W resistor instead of the standard one.

Still, it wouldn’t hurt to add protection against reverse polarity connections. We take a simple 12V car relay and two 1N4007 diodes. Also, in order to see the operating mode of the device, it would be nice to make 1 more diode and a 1kOhm 0.5W resistor.

The scheme will be like this:

Operating system: when the battery is connected with the correct polarity, the relay is turned on due to the charge remaining in the battery. After the relay is triggered charging in progress battery from the power supply through a closed relay contact, this is what the external diode will show us.

A diode, which is connected in parallel to the relay coil, serves to protect against overvoltage when it is turned off, resulting from self-induction EMF.

To glue the relay, it is better to use silicone sealant, as it will remain elastic even after drying.

Then the wires are soldered to the battery. It’s better to take flexible ones, with a cross-section of 2.5mm2, about a meter long. To connect to the battery, “crocodiles” are used at the ends of the wires. To secure them in the case, the author used a pair of nylon ties (he threaded them through the holes drilled in the radiator)

Computers cannot work without electricity. To charge them, special devices called power supplies are used. They receive AC voltage from the mains and convert it to DC. The devices can deliver enormous amounts of power in a small form factor and have built-in overload protection. Their output parameters are incredibly stable, and DC quality is ensured even under high loads. When you have an extra device like this, it makes sense to use it for many household tasks, for example, by converting it from a computer power supply into a charger.

The block has the shape of a metal box with a width of 150 mm x 86 mm x 140 mm. As standard, it is mounted inside the PC case using four screws, a switch and a socket. This design allows air to flow into the cooling fan of the power supply unit (PSU). In some cases, a voltage selector switch is installed to allow the user to select the readings. For example, in the United States there is internal source power supply operating at a nominal voltage of 120 volts.

A computer's power supply consists of several components inside: a coil, capacitors, an electronic board for regulating current, and a fan for cooling. The latter is the main cause of failure for power supplies (PS), which must be taken into account when installing a charger from an atx computer power supply.

Types of power supply for a personal computer

IPs have a certain power, indicated in watts. A standard unit is typically capable of delivering around 350 watts. The more components installed on a computer: hard drives, CD/DVD drives, tape drives, fans, the more energy is required from the power supply.

Experts recommend using a power supply that provides more power than the computer requires, as it will operate in a constant "underload" mode, which will increase the life of the machine due to the reduced thermal impact on its internal components.

There are 3 types of IP:

1. AT Power Supply - used on very old PCs.
2. ATX power supply - still used on some PCs.
3. ATX-2 power supply - commonly used today.

Power supply parameters that can be used when creating a charger from a computer power supply:

1. AT / ATX / ATX-2:+3.3 V.
2. ATX / ATX-2:+5 V.
3. AT / ATX / ATX-2: -5 V.
4. AT / ATX / ATX-2: +5 V.
5. ATX / ATX-2: +12 V.
6. AT / ATX / ATX-2: -12 V.

Motherboard connectors

The IP has many different power connectors. They are designed in such a way that there is no mistake when installing them. To make a charger from a computer power supply, the user will not have to spend a lot of time choosing the right cable, since it simply won’t fit in the connector.

Types of connectors:

1. P1 (PC/ATX connector). The main job of a power supply unit (PSU) is to provide power to the motherboard. This is done via a 20-pin or 24-pin connector. The 24-pin cable is compatible with 20-pin motherboard.
2. P4 (EPS socket): Previously, the motherboard pins were insufficient to support the processor power. With overclocking GPU, reaching 200 W, it was possible to provide power directly to the processor. Currently this is P4 or EPS which provides sufficient processor power. Therefore, converting the computer power supply into a charger is economically justified.
3. PCI-E connector (6-pin 6+2). The motherboard can provide a maximum of 75W through the PCI-E interface slot. A faster dedicated graphics card requires much more power. To solve this problem, the PCI-E connector was introduced.

Cheap motherboards are equipped with a 4-pin connector. More expensive "overclocking" motherboards have 8-pin connectors. Additional ones provide excess processor power during overclocking.

Most power supplies come with two cables: 4-pin and 8-pin. Only one of these cables needs to be used. It is also possible to split the 8-pin cable into two segments to ensure backward compatibility with cheaper motherboards.

The left 2 pins of the 8-pin connector (6+2) on the right are disconnected to ensure backward compatibility with 6-pin graphics cards. The 6-pin PCI-E connector can supply an additional 75W per cable. If the graphics card contains a single 6-pin connector, it can be up to 150W (75W from motherboard + 75W from cable).

More expensive graphics cards require an 8-pin (6+2) PCI-E connector. With 8 pins, this connector can provide up to 150W per cable. A graphics card with a single 8-pin connector can handle up to 225W (75W from motherboard + 150W from cable).

Molex, a 4-pin peripheral connector, is used when creating a charger from a computer's power supply. These pins are very long lasting and can supply 5V (red) or 12V (yellow) to peripheral devices. In the past, these compounds were often used for connecting hard discs, CD-ROM players, etc.

Even GeForce 7800 GS video cards are equipped with Molex. However, their power consumption is limited, so nowadays most of them have been replaced by PCI-E cables and all that remains are powered fans.

Accessory connector

The SATA connector is a modern replacement for the outdated Molex. All modern DVD players, hard drives and SSDs run on SATA power. The Mini-Molex/Floppy connector is completely obsolete, but some PSUs still come with a mini-molex connector. These were used to power floppy drives with up to 1.44 MB of data. They have mostly been replaced by USB storage today.

Molex-PCI-E 6-pin adapter for powering the video card.

When using a 2x-Molex-1x PCI-E 6-pin adapter, you must first make sure that both Molexes are connected to different cable voltages. This reduces the risk of overloading the power supply. With the introduction of ATX12 V2.0, changes were made to the 24-pin system. The older ATX12V (1.0, 1.2, 1.2 and 1.3) used a 20-pin connector.

There are 12 versions of the ATX standard, but they are so similar that the user does not need to worry about compatibility when installing a charger from the computer's power supply. To ensure this, most modern sources allow you to disconnect the last 4 pins of the main connector. It is also possible to create advanced compatibility using an adapter.

Computer supply voltage

The computer requires three types DC voltage. 12 volts is needed to supply voltage to the motherboard, graphic cards, for fans, processor. The USB ports require 5 volts, while the CPU itself uses 3.3 volts. 12 volts are also applicable for some smart fans. The electronic board in the power supply is responsible for sending converted electricity through special cable sets to power devices inside the computer. Using the above components AC voltage converted to pure direct current.

Almost half of the work done by a power supply is done with capacitors. They store energy that will be used for continuous work flow. When making a computer power supply, the user must be careful. Even if the computer is turned off, there is a chance that electricity will be stored inside the power supply in capacitors, even several days after the shutdown.

Cable kit color codes

Inside the power supplies, the user sees many cable sets coming out with different connectors and different numbers. Power cable color codes:

1. Black, used to provide current. Every other color must be connected to the black wire.
2. Yellow: +12V.
3. Red: +5V.
4. Blue: -12V.
5. White: -5V.
6. Orange: 3.3V.
7. Green, control wire for checking DC voltage.
8. Purple: +5V standby.

The output voltages of a computer's power supply can be measured using a proper multimeter. But due to more high risk short circuit The user should always connect the black cable with the black one on the multimeter.

Power cord plug

The wire hard drive(regardless of whether it is IDE or SATA) has four wires attached to the connector: a yellow one, two black ones in a row, and a red one. The hard drive uses both 12V and 5V at the same time. 12V powers moving mechanical parts, while 5V supplies electronic circuits. So all these cable kits are equipped with 12V and 5V cables at the same time.

The electrical connectors on the motherboard for processors or chassis fans have four legs that support the motherboard for 12V or 5V fans. Apart from black, yellow and red, other colored wires can only be seen in the main connector, which goes directly into the motherboard socket. These are purple, white or orange cables that are not used by consumers to connect peripheral devices.

If you want to make a car charger from a computer power supply, you need to test it. You will need a paperclip and about two minutes of time. If you need to reconnect the power supply to the motherboard, you just need to remove the paperclip. There will be no changes in it from using a paper clip.

Procedure:

• Find the green wire in the cable tree from the power supply.
• Follow it to a 20 or 24 pin ATX connector. The green wire is in a sense a “receiver”, which is needed to supply energy to the power supply. There are two black ground wires between it.
• Place the paperclip into the pin with the green wire.
• Place the other end into one of the two black ground wires next to the green one. It doesn't matter which one will work.

Although the paperclip will not produce a large shock, it is not recommended to touch the metal part of the paperclip while it is energized. If you need to leave a paperclip indefinitely, you need to wrap it with electrical tape.

If you start making a charger with your own hands from a computer power supply, take care of the safety of your work. The source of the threat is capacitors, which carry a residual charge of electricity that can cause significant pain and burns. Therefore, you need to not only make sure that the power supply is securely disconnected, but also wear insulating gloves.

After opening the power supply, they assess the workspace and make sure that there will be no problems with clearing the wires.

They first think through the design of the source, measuring with a pencil where the holes will be in order to cut the wires of the required length.

Perform wire sorting. In this case, you will need: black, red, orange, yellow and green. The rest are redundant, so they can be cut off on the circuit board. Green indicates power on after standby. It is simply soldered to the black ground wire, which will ensure that the power supply is turned on without a computer. Next you need to connect the wires to 4 large clamps, one for each set of colors.

After this, you need to group the 4-wire colors together and cut them to the required length, strip the insulation and connect them at one end. Before drilling holes, you need to take care printed circuit board chassis so that it is not contaminated with metal shavings.

Most PSUs cannot completely remove the PCB from the chassis. In this case, you need to wrap it carefully plastic bag. Having finished drilling, you need to treat all rough spots and wipe the chassis with a cloth to remove debris and plaque. Then install the retaining posts using a small screwdriver and clamps, securing them with pliers. After this, close the power supply and mark the voltage on the panel with a marker.

Charging a car battery from an old PC

This device will help the car enthusiast in difficult situation, when you urgently need to charge your car battery without having a standard device, but using only a regular PC power supply. Experts do not recommend constantly using a car charger from a computer power supply, since the voltage of 12 V is slightly below what is required when charging the battery. It should be 13 V, but it can be used as an emergency option. To increase the voltage where previously there was 12V, you need to change the resistor to 2.7 kOhm on the trimmer resistor installed on the additional power supply board.

Since power supplies have capacitors that store electricity for a long time, it is advisable to discharge them using a 60W incandescent lamp. To attach the lamp, use the two ends of the wire to connect to the cap terminals. The backlight will slowly go out, discharging the cover. Shorting the terminals is not recommended as this will cause a large spark and may damage the PCB traces.

The procedure for making a charger from a computer power supply with your own hands begins with removing the top panel of the power supply. If the top panel has a 120mm fan, disconnect the 2-pin connector from the PCB and remove the panel. You need to cut the output cables from the power supply using pliers. You shouldn’t throw them away; it’s better to reuse them for non-standard tasks. For each connecting post, leave no more than 4-5 cables. The rest can be trimmed on the PCB.

Wires of the same color are connected and secured using cable ties. The green cable is used to turn on the DC power supply. It is soldered to the GND terminals or connected to the black wire from the bundle. Next, measure the center of the holes on the top cover, where the fixing posts should be secured. You need to be especially careful if a fan is installed on the top panel, and the gap between the edge of the fan and the IP is small for the fixing pins. In this case, after marking the central points, you need to remove the fan.

After this, you need to attach the fixing posts to the top panel in the order: GND, +3.3 V, +5 V, +12 V. Using a wire stripper, the insulation of the cables of each bundle is removed, and the connections are soldered. Use a heat gun to heat the sleeves over the crimp connections, then insert the tabs into the connecting pins and tighten the second nut.

Next, you need to return the fan to its place, connect the 2-pin connector to the socket on the circuit board, insert the panel back into the device, which may require some effort due to the bundle of cables on the crossbars, and close it.

Charger for screwdriver

If the screwdriver has a voltage of 12V, then the user is lucky. It can make a power supply for the charger without much modification. You will need a used or new computer power supply. It has several voltages, but you need 12V. There are a lot of wires different colors. You will need yellow ones that output 12V. Before starting work, the user must make sure that the power source is disconnected from the power source and has no residual voltage in the capacitors.

Now you can start converting your computer's power supply into a charger. To do this, you need to connect the yellow wires to the connector. This will be the 12V output. Do the same for the black wires. These are the connectors into which the charger will be connected. In the block, 12V voltage is not primary, so a resistor is connected to the red 5V wire. Next you need to connect the gray and one black wire together. This is a signal that indicates energy supply. The color of this wire may vary, so you need to make sure it is the PS-ON signal. This should be written on the power supply sticker.

After turning on the switch, the power supply should start, the fan should rotate, and the light should light up. After checking the connectors with a multimeter, you need to make sure that the unit produces 12 V. If so, then the screwdriver charger from the computer power supply is functioning correctly.

In fact, there are many options for adapting the power supply to your own needs. Those who like to experiment are happy to share their experiences. Here are some good tips.

Users shouldn't be afraid to upgrade the unit's box: they can add LEDs, stickers, or anything else they need to upgrade it. When disassembling the wires, you need to make sure that you are using an ATX power supply. If it's an AT or older power supply, it will most likely have a different color scheme for the wires. If the user does not have information about these wires, he should not re-equip the unit, since the circuit may be assembled incorrectly, which will lead to an accident.

Some modern power supplies have a communication wire that must be connected to the power supply for it to work. The gray wire connects to the orange and the pink wire to the red. Power resistor with high power may get hot. In this case, you need to use a radiator for cooling in the design.

Computers cannot work without electricity. To charge them, special devices called power supplies are used. They receive AC voltage from the mains and convert it to DC. The devices can deliver enormous amounts of power in a small form factor and have built-in overload protection. Their output parameters are incredibly stable, and DC quality is ensured even under high loads. When you have an extra device like this, it makes sense to use it for many household tasks, for example, by converting it from a computer power supply into a charger.

The block has the shape of a metal box with a width of 150 mm x 86 mm x 140 mm. As standard, it is mounted inside the PC case using four screws, a switch and a socket. This design allows air to flow into the cooling fan of the power supply unit (PSU). In some cases, a voltage selector switch is installed to allow the user to select the readings. For example, in the United States there is an internal power supply that operates at a nominal voltage of 120 volts.

A computer's power supply consists of several components inside: a coil, capacitors, an electronic board for regulating current, and a fan for cooling. The latter is the main cause of failure for power supplies (PS), which must be taken into account when installing a charger from an atx computer power supply.

Types of power supply for a personal computer

IPs have a certain power, indicated in watts. A standard unit is typically capable of delivering around 350 watts. The more components installed on a computer: hard drives, CD/DVD drives, tape drives, fans, the more energy is required from the power supply.

Experts recommend using a power supply that provides more power than the computer requires, as it will operate in a constant "underload" mode, which will increase the life of the machine due to the reduced thermal impact on its internal components.

There are 3 types of IP:

1. AT Power Supply - used on very old PCs.
2. ATX power supply - still used on some PCs.
3. ATX-2 power supply - commonly used today.

Power supply parameters that can be used when creating a charger from a computer power supply:

1. AT / ATX / ATX-2:+3.3 V.
2. ATX / ATX-2:+5 V.
3. AT / ATX / ATX-2: -5 V.
4. AT / ATX / ATX-2: +5 V.
5. ATX / ATX-2: +12 V.
6. AT / ATX / ATX-2: -12 V.

Motherboard connectors

The IP has many different power connectors. They are designed in such a way that there is no mistake when installing them. To make a charger from a computer power supply, the user will not have to spend a lot of time choosing the right cable, since it simply won’t fit in the connector.

Types of connectors:

1. P1 (PC/ATX connector). The main job of a power supply unit (PSU) is to provide power to the motherboard. This is done via a 20-pin or 24-pin connector. The 24-pin cable is compatible with 20-pin motherboard.
2. P4 (EPS socket): Previously, the motherboard pins were insufficient to support the processor power. With GPU overclocking reaching 200W, the ability to provide power directly to the CPU was created. Currently this is P4 or EPS which provides sufficient processor power. Therefore, converting the computer power supply into a charger is economically justified.
3. PCI-E connector (6-pin 6+2). The motherboard can provide a maximum of 75W through the PCI-E interface slot. A faster dedicated graphics card requires much more power. To solve this problem, the PCI-E connector was introduced.

Cheap motherboards are equipped with a 4-pin connector. More expensive "overclocking" motherboards have 8-pin connectors. Additional ones provide excess processor power during overclocking.

Most power supplies come with two cables: 4-pin and 8-pin. Only one of these cables needs to be used. It is also possible to split the 8-pin cable into two segments to ensure backward compatibility with cheaper motherboards.

The left 2 pins of the 8-pin connector (6+2) on the right are disconnected to ensure backward compatibility with 6-pin graphics cards. The 6-pin PCI-E connector can supply an additional 75W per cable. If the graphics card contains a single 6-pin connector, it can be up to 150W (75W from motherboard + 75W from cable).

More expensive graphics cards require an 8-pin (6+2) PCI-E connector. With 8 pins, this connector can provide up to 150W per cable. A graphics card with a single 8-pin connector can handle up to 225W (75W from motherboard + 150W from cable).

Molex, a 4-pin peripheral connector, is used when creating a charger from a computer's power supply. These pins are very long lasting and can supply 5V (red) or 12V (yellow) to peripheral devices. In the past, these connections were often used to connect hard drives, CD-ROM players, etc.

Even GeForce 7800 GS video cards are equipped with Molex. However, their power consumption is limited, so nowadays most of them have been replaced by PCI-E cables and all that remains are powered fans.

Accessory connector

The SATA connector is a modern replacement for the outdated Molex. All modern DVD players, hard drives and SSDs run on SATA power. The Mini-Molex/Floppy connector is completely obsolete, but some PSUs still come with a mini-molex connector. These were used to power floppy drives with up to 1.44 MB of data. They have mostly been replaced by USB storage today.

Molex-PCI-E 6-pin adapter for powering the video card.

When using a 2x-Molex-1x PCI-E 6-pin adapter, you must first make sure that both Molexes are connected to different cable voltages. This reduces the risk of overloading the power supply. With the introduction of ATX12 V2.0, changes were made to the 24-pin system. The older ATX12V (1.0, 1.2, 1.2 and 1.3) used a 20-pin connector.

There are 12 versions of the ATX standard, but they are so similar that the user does not need to worry about compatibility when installing a charger from the computer's power supply. To ensure this, most modern sources allow you to disconnect the last 4 pins of the main connector. It is also possible to create advanced compatibility using an adapter.

Computer supply voltage

A computer requires three types of DC voltage. 12 volts is needed to supply voltage to the motherboard, graphics cards, fans, and processor. The USB ports require 5 volts, while the CPU itself uses 3.3 volts. 12 volts are also applicable for some smart fans. The electronic board in the power supply is responsible for sending converted electricity through special cable sets to power devices inside the computer. Using the components listed above, AC voltage is converted into pure DC current.

Almost half of the work done by a power supply is done with capacitors. They store energy that will be used for continuous work flow. When making a computer power supply, the user must be careful. Even if the computer is turned off, there is a chance that electricity will be stored inside the power supply in capacitors, even several days after the shutdown.

Cable kit color codes

Inside the power supplies, the user sees many cable sets coming out with different connectors and different numbers. Power cable color codes:

1. Black, used to provide current. Every other color must be connected to the black wire.
2. Yellow: +12V.
3. Red: +5V.
4. Blue: -12V.
5. White: -5V.
6. Orange: 3.3V.
7. Green, control wire for checking DC voltage.
8. Purple: +5V standby.

The output voltages of a computer's power supply can be measured using a proper multimeter. But due to the higher risk of short circuit, the user should always connect the black cable with the black one on the multimeter.

Power cord plug

The hard drive wire (whether it is IDE or SATA) has four wires attached to the connector: a yellow one, two black ones in a row, and a red one. The hard drive uses both 12V and 5V at the same time. 12V powers the moving mechanical parts, while 5V powers the electronic circuits. So all these cable kits are equipped with 12V and 5V cables at the same time.

The electrical connectors on the motherboard for processors or chassis fans have four legs that support the motherboard for 12V or 5V fans. Apart from black, yellow and red, other colored wires can only be seen in the main connector, which goes directly into the motherboard socket. These are purple, white or orange cables that are not used by consumers to connect peripheral devices.

If you want to make a car charger from a computer power supply, you need to test it. You will need a paperclip and about two minutes of time. If you need to reconnect the power supply to the motherboard, you just need to remove the paperclip. There will be no changes in it from using a paper clip.

Procedure:

• Find the green wire in the cable tree from the power supply.
• Follow it to a 20 or 24 pin ATX connector. The green wire is in a sense a “receiver”, which is needed to supply energy to the power supply. There are two black ground wires between it.
• Place the paperclip into the pin with the green wire.
• Place the other end into one of the two black ground wires next to the green one. It doesn't matter which one will work.

Although the paperclip will not produce a large shock, it is not recommended to touch the metal part of the paperclip while it is energized. If you need to leave a paperclip indefinitely, you need to wrap it with electrical tape.

If you start making a charger with your own hands from a computer power supply, take care of the safety of your work. The source of the threat is capacitors, which carry a residual charge of electricity that can cause significant pain and burns. Therefore, you need to not only make sure that the power supply is securely disconnected, but also wear insulating gloves.

After opening the power supply, they assess the workspace and make sure that there will be no problems with clearing the wires.

They first think through the design of the source, measuring with a pencil where the holes will be in order to cut the wires of the required length.

Perform wire sorting. In this case, you will need: black, red, orange, yellow and green. The rest are redundant, so they can be cut off on the circuit board. Green indicates power on after standby. It is simply soldered to the black ground wire, which will ensure that the power supply is turned on without a computer. Next you need to connect the wires to 4 large clamps, one for each set of colors.

After this, you need to group the 4-wire colors together and cut them to the required length, strip the insulation and connect them at one end. Before drilling holes, you need to take care of the chassis circuit board so that it is not contaminated with metal shavings.

Most PSUs cannot completely remove the PCB from the chassis. In this case, it must be carefully wrapped in a plastic bag. Having finished drilling, you need to treat all rough spots and wipe the chassis with a cloth to remove debris and plaque. Then install the retaining posts using a small screwdriver and clamps, securing them with pliers. After this, close the power supply and mark the voltage on the panel with a marker.

Charging a car battery from an old PC

This device will help the car enthusiast in a difficult situation when he urgently needs to charge the car battery without having a standard device, but using only a regular PC power supply. Experts do not recommend constantly using a car charger from a computer power supply, since the voltage of 12 V is slightly below what is required when charging the battery. It should be 13 V, but it can be used as an emergency option. To increase the voltage where previously there was 12V, you need to change the resistor to 2.7 kOhm on the trimmer resistor installed on the additional power supply board.

Since power supplies have capacitors that store electricity for a long time, it is advisable to discharge them using a 60W incandescent lamp. To attach the lamp, use the two ends of the wire to connect to the cap terminals. The backlight will slowly go out, discharging the cover. Shorting the terminals is not recommended as this will cause a large spark and may damage the PCB traces.

The procedure for making a charger from a computer power supply with your own hands begins with removing the top panel of the power supply. If the top panel has a 120mm fan, disconnect the 2-pin connector from the PCB and remove the panel. You need to cut the output cables from the power supply using pliers. You shouldn’t throw them away; it’s better to reuse them for non-standard tasks. For each connecting post, leave no more than 4-5 cables. The rest can be trimmed on the PCB.

Wires of the same color are connected and secured using cable ties. The green cable is used to turn on the DC power supply. It is soldered to the GND terminals or connected to the black wire from the bundle. Next, measure the center of the holes on the top cover, where the fixing posts should be secured. You need to be especially careful if a fan is installed on the top panel, and the gap between the edge of the fan and the IP is small for the fixing pins. In this case, after marking the central points, you need to remove the fan.

After this, you need to attach the fixing posts to the top panel in the order: GND, +3.3 V, +5 V, +12 V. Using a wire stripper, the insulation of the cables of each bundle is removed, and the connections are soldered. Use a heat gun to heat the sleeves over the crimp connections, then insert the tabs into the connecting pins and tighten the second nut.

Next, you need to return the fan to its place, connect the 2-pin connector to the socket on the circuit board, insert the panel back into the device, which may require some effort due to the bundle of cables on the crossbars, and close it.

Charger for screwdriver

If the screwdriver has a voltage of 12V, then the user is lucky. It can make a power supply for the charger without much modification. You will need a used or new computer power supply. It has several voltages, but you need 12V. There are many wires of different colors. You will need yellow ones that output 12V. Before starting work, the user must make sure that the power source is disconnected from the power source and has no residual voltage in the capacitors.

Now you can start converting your computer's power supply into a charger. To do this, you need to connect the yellow wires to the connector. This will be the 12V output. Do the same for the black wires. These are the connectors into which the charger will be connected. In the block, 12V voltage is not primary, so a resistor is connected to the red 5V wire. Next you need to connect the gray and one black wire together. This is a signal that indicates energy supply. The color of this wire may vary, so you need to make sure it is the PS-ON signal. This should be written on the power supply sticker.

After turning on the switch, the power supply should start, the fan should rotate, and the light should light up. After checking the connectors with a multimeter, you need to make sure that the unit produces 12 V. If so, then the screwdriver charger from the computer power supply is functioning correctly.

In fact, there are many options for adapting the power supply to your own needs. Those who like to experiment are happy to share their experiences. Here are some good tips.

Users shouldn't be afraid to upgrade the unit's box: they can add LEDs, stickers, or anything else they need to upgrade it. When disassembling the wires, you need to make sure that you are using an ATX power supply. If it's an AT or older power supply, it will most likely have a different color scheme for the wires. If the user does not have information about these wires, he should not re-equip the unit, since the circuit may be assembled incorrectly, which will lead to an accident.

Some modern power supplies have a communication wire that must be connected to the power supply for it to work. The gray wire connects to the orange and the pink wire to the red. A high wattage power resistor may become hot. In this case, you need to use a radiator for cooling in the design.