A dimmable power supply or laboratory power supply has many uses in the field of computing and science.In this article, we are going to give you all the keys about this unknown component.Table of contents This is an adjustable power supplyWhat is alternating current and direct currentWhat is voltage and electric currentAn adjustable power supply controls the voltage and limits the currentIn what areas is an adjustable power supply used?Tips for buying a power supply adjustable power supplyBuild your own laboratory power supply!Easy solution: with fixed voltagesAdvanced solution: with a buck-boost converterThis is an adjustable power supplyThe main characteristic of a power supply, like the ones we use in our computers, consists of the ability to transform and rectify the alternating current of our homes, so that it becomes a direct current of lower voltage.To put ourselves in context, we are going to define some of the concepts used in this generic definition of a power supply.Then, we will enter the field of adjustable.As we say, the source will go from alternating current to direct current.What do both concepts mean?On these first two points, what we have to understand is that a power supply goes from alternating current to direct current, since the latter is what the electronic components need.Graphically observe the process: first we reduce the voltage (now we define it) through transformation, then through rectification (with a diode bridge) we eliminate the negative part of the alternating current to keep only the positive, this would be a pulsating current that It is intermediate between alternating and continuous.Finally, thanks to the capacitors, the pulsating current is smoothed out, and something stable enough to be called direct current is passed.That would be the simplified process, in practice switch mode power supplies (SMPS) are used which are better and more efficient, but more difficult to understand.We can give an analogy to understand what voltage and current are.In a water pipe (equivalent to a cable), the voltage would be equivalent to the hydraulic pressure, and the current would be equivalent to the hydraulic flow.In almost any adjustable power supply, we will find two displays, one with a value in Volts (V) and another with a value in Amps (A).These will change depending on what we do on the rotating cursors that we can find to vary the voltage and amperage.If the source is in constant voltage or Constant Voltage (CV) mode, we can do these two things:Voltage regulation provides us with versatility, because it means that we can test the source with anything, and current limitation gives us security, because it will prevent damaging or breaking components, and even helps us prevent a short circuit from being catastrophic.Similarly, the source can work in constant current or Constant Current (CC) mode, in which we choose the current we want to deliver, and what will vary is the voltage.It is also a safe mode because if, for example, we cause a short circuit, the voltage will go to 0. So, remember that we usually have CC mode and CV mode.It is also a safe mode because if, for example, we cause a short circuit, the voltage will go to 0.So, remember that we usually have CC mode and CV mode.At all times, we will be able to see what is happening thanks to the screen or screens, which will show the voltage, amperage and the current operating mode (CC / CV).And how do you connect the electrical components to a dimmable source?In general, it has 3 outputs (Positive, Negative and an output to the ground of our electrical network), which we can connect or disconnect, and at its end they will be metal clamps.As we say, an adjustable power supply is also known as a laboratory power supply.In any scientific field where electronic components are tested, there is going to be such a power supply.Can you imagine being an electrical engineer and having a mountain of sources or chargers for each of the circuits and components you test?Obviously, it is much more practical to have a single source that you can vary the voltage or current to test everything.Therefore, adjustable sources are an essential component of any electronics laboratory, combined with many others:The uses of these fonts are innumerable.For example, at Professional Review we often use a "homemade" adjustable power supply to test the fans of the PC power supplies we review, and check how the fan spins based on the applied voltage.You should know that there are many adjustable power supplies available on the market, for a price of around 50 euros for basic models, 100-150 for intermediate models and we can even see them for more than 1000 euros for professional adjustable supplies.What should we pay attention to when choosing an adjustable source?As well:We must also take into account that if we choose very cheap models they could provide a "dirtier" current than normal, that is, with a high ripple.This is something that you can check if you have an oscilloscope in your laboratory, but it is not usually a problem.Last updated on 2022-10-11(UNI-T multimeters are often recommended by experts due to their value for money)Another important issue is voltage accuracy.Having a multimeter, even a basic one like the one we recommend above, is absolutely necessary to verify that the power supply is delivering the voltage it indicates and avoid problems.Last updated on 2022-10-11That said, an example of a laboratory power supply for basic uses is this Eventek that we can find on Amazon for €55 (0-5A version) or €70 (0-10A version).In both cases it reaches up to 30V.Last updated on 2022-10-11If you need robustness, precision and reliability, RIGOL provides its 195W DP800 sources, keep in mind that these are linear sources rather than switching sources.We all use switching power supplies for efficiency and price, but the linear ones regulate the voltage more precisely: we are talking about differences of 10mV and 10mA in this Rigol power supply, so it is aimed at a very niche audience.If you don't want to spend money on a dimmable power supply, you can build your own at home, taking advantage of a computer power supply or even a charger.We present you with two options, but keep in mind that working with electricity is not a joke, since the sources always have a part exposed to the electrical network of the house, that if we touch without protection they will electrocute us, which is a risk to life .The easiest way to build a laboratory power supply is to take advantage of the multiple voltages that are provided in a computer power supply.In general, these are 12V, 5V, 3.3V and -12V.What people do is cut the output cables of the power supply (which have a specific associated voltage) and place metal connectors on the power supply like those of adjustable power supplies, one for each voltage and another for the negative.Thus, we can make various interesting combinations.In addition to the 12V, 5V, 3.3V and -12V output, we can change the negative at will and form new voltages: for example, if we connect 12V to the positive and 5V to the negative, we will have 7V (12-7).Or if we have 12V on the positive and -12V on the negative, we will have 24V.In short, don't do this if you don't have an electronics background or if you need the source for a trusted environment.We do not advise it.It is best to buy a laboratory source and forget about problems.A much more sophisticated way to make a lab power supply is to purchase a buck-boost converter.Buck-boost converters are DC-DC converters, that is, they have direct current as input and also as output, but in the process they regulate the voltage efficiently and precisely.They are also very cheap.Thus, we would not have to use the fixed voltages of a PC power supply, plus we could use it with a mobile or laptop charger, or a 12V power supply.As always, with the necessary precautions and always with sufficient knowledge.The video above shows us how to do it in a very intuitive and interesting way, check it out.We recommend reading the best power supplies on the market for PCs.This ends our article on laboratory power supplies, we hope you have understood all the associated electricity concepts, otherwise you can leave a comment so that we can clarify it for you.Thanks for reading us!In Professional Review you will find all the most interesting analyses, news and tutorials.Specialists in hardware, PC configurations, peripherals, software, smartphones and any technological product that we see interesting.Join our community!