How to make a power supply controlled by your own hands

From the article you will learn how to make a power supply controlled by hand from available materials. It can be used for powering household appliances, as well as for the needs of its own laboratory. A DC voltage source can be used to test devices such as a car generator relay relay. After all, when it is diagnosed, there is a need for two voltages - 12 volts and over 16. And now consider the design features of the power supply.

Transformer

If the device is not intended to be used for charging acid batteries and powering powerful equipment, then there is no need to use large transformers. It is enough to apply models whose power is not more than 50 W. However, in order to make an adjustable power supply by yourself, it will be necessary to slightly change the design of the converter. First of all, you need to determine what range of voltage changes will be at the output. The characteristics of the power supply transformer depend on this parameter.

Suppose you chose a range of 0-20 volts, then you need to repulse from these values. The secondary winding should have an output voltage of 20-22 Volts. Therefore, on the transformer you leave the primary winding, on top of it wind the secondary winding. To calculate the required number of turns, measure the voltage, which is obtained from ten. The tenth part of this value is the voltage received from one turn. After the secondary winding is made, it is necessary to assemble and clamp the core.

Rectifier

As a rectifier, you can use both assemblies and individual diodes. Before making an adjustable power supply, please select all of its components. If the current is high at the output, then you will need to use high-power semiconductors. It is desirable to install them on aluminum radiators. As for the circuit, the preference should only be given to the bridge, since it has much higher efficiency, less voltage loss when rectifying the AC. A half-wave circuit is not recommended, since it is ineffective, many pulsations occur at the output, which distort the signal and are a source of interference for radio equipment.

Stabilization and adjustment unit

For the manufacture of a stabilizer and a voltage regulator, it is most reasonable to use the microassembly LM317. Cheap and affordable to each device, which will allow for a few minutes to assemble a high-quality power supply controlled by their own hands. But its application requires one important detail - effective cooling. And not only passive in the form of radiators. The fact is that the regulation and stabilization of the voltage occur according to a very interesting scheme. The device leaves exactly the voltage that is needed, but the excesses coming to its input are converted into heat. Therefore, without cooling, micro-assembly is unlikely to work long.

Look at the diagram, there is nothing super complicated in it. There are only three outputs from the assembly, the third is supplied with voltage, the second is removed, and the first is needed to connect to the minus supply unit. But here there is a small feature - if you include a resistance between the minus and the first terminal of the assembly, it becomes possible to adjust the voltage at the output. Moreover, the power supply controlled by the hands can change the output voltage both smoothly and stepwise. But the first type of adjustment is the most convenient, so it is used more often. For implementation, it is necessary to include an impedance of 5 kΩ. In addition, between the first and second terminal of the assembly it is required to install a constant resistor with a resistance of about 500 Ohm.

Current and voltage control unit

Of course, to use the device as convenient as possible, it is necessary to monitor the output characteristics - voltage and amperage. The circuit of the regulated power supply unit is constructed in such a way that the ammeter is connected to the break of the positive wire, and the voltmeter is connected between the outputs of the device. But the question in the other is what type of measuring instruments to use? The simplest option is to install two LED-displays, to which to connect the circuit of the volt- and ammeter, assembled on one microcontroller.

But in the power supply is an adjustable, self-made, you can mount a pair of cheap Chinese multimeters. The benefit of their food can be made directly from the device. Of course, you can also use the arrow indicators, only in this case you need to scale the scale for the variable resistor.

Device body

The body is best made of lightweight but durable metal. The ideal option is aluminum. As already mentioned, the circuit of the regulated power supply contains elements that heat up strongly. Therefore, inside the case you need to mount a radiator, which for greater efficiency can be connected with one of the walls. Presence of forced blowing is desirable. For this purpose, you can use a thermal switch paired with a fan. Install them directly on the cooling radiator.