Power supplies have always been important elements of any electronic devices. These devices are involved in amplifiers as well as receivers. The main function of power supplies is considered to be the reduction of the limiting voltage that comes from the network. The first models appeared only after the alternating current coil was invented.
In addition, the development of power supplies was affected by the introduction of transformers in the device circuit. The peculiarity of pulse models is that they use rectifiers. Thus, the voltage stabilization in the network is carried out in a slightly different way than in conventional devices where the converter is used.
Power supply device
If we consider a conventional power supply, which is used in radios, then it consists of a frequency transformer, transistor, as well as several diodes. Additionally, a choke is present in the circuit. Capacitors are installed in different capacities and can vary greatly in parameters. Rectifiers are used, as a rule, of the capacitor type. They belong to the category of high voltage.
The work of modern blocks
Initially, voltage is supplied to the bridge rectifier. At this stage, the peak current limiter is activated. This is necessary so that the fuse does not burn out in the power supply. Further, the current passes through the circuit through special filters, where it is converted. Several capacitors are needed to charge the resistors. The node starts only after the breakdown of the dinistor. Then, the transistor is unlocked in the power supply. This makes it possible to significantly reduce self-oscillations.
When voltage generation occurs, diodes in the circuit are activated. They are interconnected by cathodes. The negative potential in the system makes it possible to lock the dinistor. Facilitation of starting the rectifier is carried out after locking the transistor. Additionally, current limitation is provided. To prevent saturation of the transistors, there are two fuses. They work in the circuit only after a breakdown. To start feedback, a transformer is required. Pulse diodes feed it in the power supply. At the output, alternating current passes through capacitors.
Features of laboratory blocks
The principle of operation of switching power supplies of this type is based on active current conversion. The bridge rectifier in the standard circuit is one. In order to remove all interference, filters are used at the beginning and also at the end of the circuit. Capacitors switching laboratory power supply has conventional. The saturation of transistors occurs gradually, and this has a positive effect on diodes. Voltage adjustment is provided in many models. The protection system is designed to save blocks from short circuits. Cables for them are usually used in the non-modular series. In this case, the power of the model can reach up to 500 watts.
The connectors of the power supply in the system are most often installed type ATX 20. To cool the unit, a fan is mounted in the housing. The speed of rotation of the blades should be regulated. The laboratory-type unit must be able to withstand the maximum load at 23 A. At the same time, the resistance parameter is maintained at an average of 3 ohms. The limit frequency that a pulsed laboratory power supply has is 5 Hz.
How to repair devices?
Most often, power supplies suffer from blown fuses. They are located near the capacitors. Start repairing switching power supplies by removing the protective cover. Next, it is important to examine the integrity of the chip. If defects are not visible on it, it can be checked using a tester. To remove the fuses, you must first disconnect the capacitors. After that, they can be removed without problems.
To check the integrity of this device inspect its base. Blown fuses at the bottom have a dark spot that indicates damage to the module. To replace this element, you need to pay attention to its marking. Then in the electronics store you can purchase a similar product. The fuse is installed only after the condensates have been fixed. Another common problem in power supplies is considered to be malfunctions with transformers. They are boxes in which coils are installed.
When the voltage is supplied to the device is very large, they can not withstand. As a result, the integrity of the winding is violated. It is impossible to repair pulse power supplies with such a breakdown. In this case, the transformer, like the fuse, can only be replaced.
Power supplies
The principle of operation of switching power supply units of a network type is based on a low-frequency reduction in the amplitude of interference. This is due to the use of high voltage diodes. Thus, it is more efficient to control the limit frequency. Additionally, it should be noted that transistors are used medium power. The load on the fuses is minimal.
Resistors are rarely used in the standard circuit. This is largely due to the fact that the capacitor is able to participate in the conversion of current. The main problem of this type of power supply is the electromagnetic field. If capacitors are used with low capacitance, the transformer is at risk. In this case, you should be very careful about the power of the device. The surge current network has limiters for peak current, but they are located directly above the rectifiers. Their main task is to control the operating frequency to stabilize the amplitude.
Diodes in this system partially serve as fuses. To start the rectifier, only transistors are used. The locking process, in turn, is necessary to activate the filters. Capacitors can also be used with a separation type in the system. In this case, the start of the transformer will be much faster.
Chip application
Microchips in power supplies use the most diverse. In this situation, a lot depends on the number of active elements. If more than two diodes are used, then the board must be designed for input and output filters. Transformers are also produced in different capacities, and in size they are quite different.
You can solder microcircuits yourself. In this case, it is necessary to calculate the ultimate resistance of the resistors taking into account the power of the device. To create an adjustable model using special blocks. This type of system is made with double tracks. Ripples inside the board will occur much faster.
Advantages of Adjustable Power Supplies
The principle of operation of switching power supplies with regulators is to use a special controller. This element in the circuit can change the throughput of transistors. Thus, the limit frequency at the input and output is significantly different. You can configure the pulse power supply in different ways. Voltage adjustment is carried out taking into account the type of transformer. To cool the device using conventional coolers. The problem with these devices is usually an overcurrent. In order to solve it, use protective filters.
The power of the devices fluctuates on average around 300 watts. Cables in the system are used only non-modular. Thus, short circuits can be avoided. The power supply connectors for connecting devices are usually installed in the ATX 14 series. The standard model has two outputs. Rectifiers are used high voltage. Resistance they can withstand at 3 ohms. In turn, the maximum load the switching adjustable power supply takes up to 12 A.
12 volt blocks
Switching power supply (12 volts) includes two diodes. At the same time, filters are installed with a low capacity. In this case, the pulsation process is extremely slow. The average frequency fluctuates around 2 Hz. The efficiency of many models does not exceed 78%. These blocks also differ in their compactness. This is due to the fact that transformers are installed at low power. In this case, they do not need cooling.
The 12V switching power supply circuit additionally implies the use of resistors marked P23. Resistance they can withstand only 2 ohms, however, such a power is enough for the device. A 12V switching power supply is used most often for lamps.
How does the unit for the TV?
The principle of operation of switching power supplies of this type is the use of film filters. These devices are able to cope with interference of various amplitudes. The inductor winding is provided for them synthetic. Thus, the protection of important nodes is ensured by high-quality. All gaskets in the power supply are isolated from all sides.
The transformer, in turn, has a separate cooler for cooling. For ease of use, it is usually installed silently. The temperature limit these devices withstand up to 60 degrees. The operating frequency of the switching power supply of the TVs is maintained at 33 Hz. At subzero temperatures, these devices can also be used, but much in this situation depends on the type of condensates used and the cross section of the magnetic circuit.
24 volt device models
In 24-volt models, low-frequency rectifiers are used. With interference, only two diodes can successfully cope. The efficiency of such devices is able to reach up to 60%. Regulators for power supplies are rarely installed. The operating frequency of the models on average does not exceed 23 Hz. Resistors can only withstand 2 ohms. Transistors in models are installed with the marking PR2.
To stabilize the voltage, resistors are not used in the circuit. Filters The 24V switching power supply has a capacitor type. In some cases, you can find dividing types. They are necessary to limit the limiting current frequency. To quickly start the rectifier, dinistors are rarely used. The negative potential of the device is removed using the cathode. At the output, the current is stabilized by locking the rectifier.
DA1 power supplies
Power supplies of this type differ from other devices in that they can withstand heavy loads. There is only one capacitor in the standard circuit. For normal operation of the power supply, the regulator is used. The controller is installed directly next to the resistor. There are no more than three diodes in the circuit.
The directly reverse conversion process begins in the dinistor. To start the unlocking mechanism, a special choke is provided in the system. Waves with large amplitude are quenched at the capacitor. It is usually installed in a separation type. Fuses in the standard circuit are rare. It is justified by the fact that the limit temperature in the transformer does not exceed 50 degrees. Thus, the ballast throttle copes with its tasks independently.
Models of devices with DA2 chips
Chips of pulse power supplies of this type, among other devices, are distinguished by increased resistance. Use them mainly for measuring instruments. An example is an oscilloscope that shows vibrations. Stabilization of voltage is very important for him. As a result, the performance of the device will be more accurate.
Many models are not equipped with regulators. Filters are mainly double-sided. Transistors are installed at the output of the circuit. All this makes it possible to withstand the maximum load at 30 A. In turn, the limit frequency indicator is at around 23 Hz.
Blocks with DA3 Chips Installed
This chip allows you to install not only the controller, but also the controller, which monitors the fluctuations in the network. Resistance transistors in the device can withstand about 3 ohms. A powerful DA3 switching power supply with a load of 4 A copes. You can connect fans to cool the rectifiers. As a result, the device can be used at any temperature. Another advantage is the presence of three filters.
Two of them are installed at the inlet under the capacitors. One isolating filter is provided at the output and stabilizes the voltage that comes from the resistor. There are no more than two diodes in the standard circuit. However, much depends on the manufacturer, and this should be considered. The main problem of this type of power supply is that they are not able to cope with low-frequency interference. As a result, installing them on measuring instruments is impractical.
How does the unit work on VD1 diodes?
These blocks are designed to support up to three devices. Regulators in them are tripartite. Cables for communication are installed only non-modular. Thus, current conversion is fast. Rectifiers in many models are installed in the KKT2 series.
They differ in that they can transmit energy from the capacitor to the winding. As a result, the filter load is partially removed. The performance of such devices is quite high. At temperatures above 50 degrees, they can also be used.