How to make a simple power supply of ready-made modules with AliExpress

If you are just at the beginning of an interesting and sometimes difficult journey to study electronics, then the question where to get an adjustable power supply, can get quite serious. Of course, you can buy ready-made power supply, but it is much cheaper to do it yourself already from prefabricated modules (especially since it's much easier than it sounds), than this article, we are going to do with you.

preparation of material

So, in order to collect a simple power supply with adjustable voltage only we need the following components: Power Supply Module AC 220V to DC 24V, Banana Soket, DC / DC converters a controlled input and output voltage, Voltmeter, ammeter (Reference to the components themselves will be at the end of the article). Overall total cost of all the modules made - 797.14 rubles. The case itself and the power cord, I decided to look at their holdings.

Assembly

So finally, after waiting until all the parts are delivered, I began to assemble a simple controlled power supply of ready-made modules.

As boxing, I decided to use a body from their exhaust BP / TEL unit - 220 - 02A. Inside this body just fit all compact modules.

In principle, you can use absolutely any body with dimensions: 19h13h7 centimeters or even collect it from a piece of karbolit or Plexiglas.

On the cover of the case I adjusted Indicative hole connectors such as banana, and a voltmeter - ammeter and a regulator, I decided to place on the side of the hull.

The circuit connection of these modules is very simple and as follows:

Now, according to the scheme above just simply put our blocks to each other and fasten them inside the case.

Note. Block DM 703-M401 does not have on-board inscriptions in English, only in Chinese. And if you do not know, it is quite difficult to know where the entrance is, and where the voltage output.

Searching information on the block, I found the following:

Ready unit is as follows.

Thus, voltage control is performed in the range from 1.25 volts to 36 volts, but since the downconverter 220 Volt is designed for 24 volts, it is already our adjustable unit will issue a maximum of 24 volts, and the maximum current is then equal to 6 Amps.

Thus in this charger is not regulated current limiting is provided.

To implement such a lock should be replaced with a block DC / DC converters and supply, e.g., this block and also to purchase a pair of adjustable resistors, you get a power supply with the possibility of blocking the current.

Testing parameters and performance

So, our power supply is ready, now is the time to experience it. First of all check the voltage which in reality give our modules and shows exactly how our voltmeter. Check on the parameters I will perform mulmetrom Mastech MY68.

As seen from the figure above the power unit (on the meter readings) outputs a voltage 0.814 volts is already at the start, i.e. at the beginning can not receive the "net" zero. The difference in the readings of the meter and the volt-ammeter is 0.014 volts, which within the error.

With the voltage rises, the difference in the readings. So, at 25 volts (the limit value for the power supply), it is 0.7 volts, while 12 volts difference is 0.45 volts.

Now let's test the behavior of the unit load. To do this, connect a regular car bulb 12 volts.

Under load, so the difference with a voltmeter and multimeter was 0.4 volts.

Now, as the load is connected galogenki.

From all the above, it is possible to make an interim conclusion that under load drawdown voltage is not observed, but with the current indications of trouble.

Check the ammeter shows that his testimony differ substantially from the meter reading.

And the adjustment given nothing trimmer.

Note. Voltmeter - ammeter I found unfit, which is immediately reported to the seller and provided photos to which he apologized and sent a new block. And since our power supply design is modular, replace the worthless item is very simple.

conclusion

If you need a simple power supply at the lowest cost, that is the best option, and experience in the assembly ever will not be superfluous. Here, as promised links to components: step-down unit, with the regulator converter, connectors, ammeter - voltmeter.

If the article was useful to you, or are interested in, you will appreciate it Like. And thank you for your attention!