The article will talk about how to make ULF with your own hands from improvised materials. And preference will be given only to those designs that can be repeated even by a beginner amateur, who just learned to read electrical schematic diagrams. But first things first. To begin with, it is worth noting that there are four types of circuits: on lamps, transistors, microcircuits, as well as mixed, which can contain several types of elements. For example, a preamplifier can be assembled on transistors, and a terminal one on lamps.
Which scheme to choose?
It is worth deciding what you expect from the device and in what area you intend to use it. It depends on which VLF scheme will be used. But in any case, of course, the choice of a modern element base is the most effective solution. Please note that the lamp technology has a huge drawback - a massive power supply. And now it will be extremely difficult to find transformers. And if there is no supply of lamps, then if one fails, you will lose your amplifier. It is quite simple to make ULF lamps on your own with your own hands , only the design is cumbersome.
Transistor designs look more attractive, but they also have a big minus. With the apparent complexity of the circuit, you get very low power. It is likely that you can get a huge printed circuit board on which the elements will be located close to each other, and the power of this entire device - no more than 10 watts. Therefore, the third option remains - the use of microcircuits. Simple, reliable, durable (with proper use).
Printed circuit board
Installation can be done in a small area, so a piece of foil material with a size of 30x30 mm is enough for you. But you can apply the so-called fish - textolite with holes for mounting elements and small areas of metal around them. This will be the most optimal solution. Making a simple ULF with your own hands is a matter of several minutes.
If there is only foil textolite, then you will have to cut grooves on it. They will make it possible to make a few patch of copper on a small board. They will be the installation of all elements of the amplifier. Please note that the power supply can be performed both separately from the main part of the ULF, and together with it.
Power amplifier
As a rule, for household amplifiers there is enough power at 9-18 volts. These are standard voltages; transformers can be found almost everywhere. The standard power scheme is a transformer, four diodes and a capacitor with a capacity of at least 100 μF to get rid of the variable component of the supply voltage.
But a lot depends on which particular ULF scheme will be used in your design. If you plan to assemble a low-power VLF, then you need to look at the datasheet of the microcircuit that you are going to apply. Pay particular attention to the line that indicates the voltage range. If a reduction to 5 V is permissible, then any charger from the phone can be used.
How to assemble an amplifier
VLF on microcircuits needs additional cooling. Sometimes even low-power structures emit a large amount of heat. Therefore, it is imperative to use aluminum radiators for efficient cooling.
If you are building a powerful ULF with your own hands, you should carefully consider the issue of cooling. It is possible that additional installation of a cooler is required.
In general, assembling the ULF with your own hands should not be difficult. All elements are connected according to the scheme. And after the verification check and the chimes, power is supplied and the signal source is connected to the input. Of course, the output needs a load - a speaker. With a working microcircuit, the amplifier starts working without settings. It is worth noting that the amplifier circuit is best used exactly the one that is given in the microcircuit datasheet. These typical schemes take into account all, even the smallest nuances of a particular microcircuit. And it will work well only taking into account these nuances. Using circuits from unverified sources, you risk damaging the chip. And sometimes its cost is quite high.