Do-it-yourself low-frequency tension booster. Low frequency booster economy class

High input and shallow OS is the main secret of warm tube sound. It’s no secret that the lamps themselves implement the highest and most expensive boosters that reach the HI-End category. I understand, what is this bright booster? It is clear that it has the right to be called that low-frequency boost, which exactly repeats the shape of the input signal at the output, without contradicting it, obviously, the output signal is already amplified. At the same time, you can find a number of circuits of effectively high-voltage boosters, which may belong to the HI-End category and are not at all obligatory lamp circuits. To obtain the maximum ductility, a booster is required, the output stage of which operates in pure class A. The maximum linearity of the circuit gives a minimum amount of interference at the output, which will result in high-voltage boosters Yuvachiv pays special respect to this factor itself. The lamp circuits are good, but not always available for self-assembly, and commercial lamp UMZCHs from branded generators cost several thousand, up to several tens of thousands of US dollars - this price is definitely not unreasonable and rich.
It's the power supply that's to blame - how can similar results be achieved in transistor circuits? The answer will be purely statistical.

There are a lot of linear and super-linear circuits that enhance the tension of the low frequencies, as well as the circuit that will be reviewed today, and the ultra-linear circuit with high luminosity, which is implemented entirely on 4 transistors. The circuit was created back in 1969 by British audio engineer John Linsley-Hood. The author is the creator of many more high-voltage circuits, including class A. Some experts call this the most powerful medium of transistor ULFs, and I have already converted to this.

The first version of this booster was presented on. After testing the implementation of the circuits, it became possible to create a dual-channel ULF behind the same circuit, taking everything from the case and vicoristats for special needs.

Features of the schemes

Despite its simplicity, the scheme contains a number of peculiarities. The correct operating mode can be disrupted through incorrect distribution of components, incorrect installation of components, etc.
The life itself is a particularly important factor - I wouldn’t be happy to live with this power supply from powerful life units, the optimal option is a battery or a life unit with a parallel connected battery.
The voltage of the power supply is 10 watts with 16 volts at 4 ohms. The circuit itself can be adapted for 4, 8 and 16 Ohm heads.
I created a stereophonic version of the booster, with the channels distributed on one board.

The other is for the purpose of diversifying the output cascade by installing KT801 (it is important to obtain it.
At the output stage, placing tight bipolar switches of the turning conductor - KT803, along with them, removing the incredibly high sound brilliance, wanting to experiment with a wide variety of transistors - KT805, 819, 808, finally placing on tighter warehouses - KT827, with it the tightness is richer, but the sound is comparable to KT803 , although this is just my subjective thought.

The vhidny capacitor to the 0.1-0.33MKF, Treasel Vikoristovati Plivkovi Condensatori with the Minimalm Vitok, Bazhano Vidomikh Vobronyv, those sama і і Х Х Х Х ХО Х Х ХО Х Х ХО Х Х ХО Х Х ХО Х Х ХО Х Х Х Х Х ХО Х Х Х ХО Х Х Х ХО Х ХО Х ХО Х ХО Х ХО Х Х Х ХО Х Х ХО Х Х ХО Х ХО Х Х ХО Х Х ХО Х Х ХО Х ХО Х Х ХО Х ХО Х ХО Х ХО Х ХО Х ХО Х І і і і і і Х ХО Х ХО Х ХО Х ХО Х said.
If the circuit is designed for 4 ohms, then it is not possible to push the voltage higher than 16-18 volts.
If you don’t install the sound regulator, it also affects the sound, but you should put a 47k resistor in parallel with the input and minus.
The board itself is prototype. I had to tinker with the board for a long time, the fragments of the line of tracks were already contributing to the harshness of the sound as a whole. This booster has a very wide range of frequencies that can be achieved, from 30 Hz to 1 MHz.

Setting up is as simple as shelling pears. For this purpose, a changeable resistor can be used to achieve half the voltage at the output. For more precise adjustment, use a reverse exchangeable resistor. One multimeter signal is added minus the life, the other is placed to the line output, then plus the electrolyte at the output, in this way, completely wrapping up the changer, we achieve half of the life at the output.

I would like to introduce one of the detailed and tested ULF circuits to the fans of bright sound creation. This design will help to create an acidic booster that can be further refined with minimal waste and a victorious booster for tracking circuit solutions.

This will help you in everything from simple to complex and complete. Before the description, there are files of other boards that can be transformed to fit a specific case.

The presented version has a vikoristic housing made of U-101 radio equipment.

I have unburdened and profited from this intense effort in the past century from what could have been gained without difficulty. I wanted to create a design with the highest possible price and performance ratio. This is not High-End, but not third grade. It is clear-sounding, eminently repeatable and simple in perfection.

Principle diagram of the booster

The circuit is completely symmetrical for the positive and negative side of the low-frequency signal. The input stage is connected to transistors VT1 – VT4. The prototype is equipped with transistors VT1 and VT4, which increases the linearity of cascades on transistors VT2 and VT3. There are no circuit variations of input cascades, which result in different advantages and disadvantages. This cascade of connections through simplicity, the ability to reduce the nonlinearity of the amplitude characteristics of transistors. With the appearance of detailed circuits of the input cascades, it is possible to replace them.

The negative feedback signal (NCC) is taken from the output of the voltage booster and goes to the emitter pins of transistors VT2 and VT3. Vidmova's undercover OOS is determined to force the flow into the OOS of anyone who is not an output signal of the circuit. Each has its own pros and cons. For this complete set it is justified. With clear components, you can try with different types of collars.

As a stress booster, the cascode circuit is designed with a large input support, a small flow capacity and smaller nonlinear gates in the same circuit as the OE circuit. The short cascade circuit has a smaller amplitude of the output signal. This is payment for less trouble. Once you install jumpers, you can select an OE circuit on the other board. The life of the voltage booster from the main voltage core was not transmitted through the power supply due to the design of the ULF.

The output stage is a parallel booster, so it has a number of advantages over other circuits. One of the important advantages is the linearity of the circuits with a significant distribution of transistor parameters, which was verified during the selection of the booster. This cascade is due to the mother, perhaps, more linearity, because There is no negative feedback and there is no capacity for the output signal of the booster. Power supply voltage 30 Art.

Design of the support

I have distributed additional payments for available cases in the form of Radiotekhnika U-101 subs. A diagram of placing two parts of a wooden board. On the first part, which is fixed to the radiator, there is a “parallel” power supply and voltage booster. The other part of the board houses the input stage. This board is attached to the first board with additional pins. In this way, dividing the payment into two parts makes it possible to carry out improved support with minimal constructive changes. In addition, such a layout can be used for laboratory tracking of cascades.

It is necessary to select strength in several stages. The folding begins with parallel support and improvement. The next step is to improve the solution of the circuits and carry out the residual minimization of the disturbances of the circuits. When placing the transistors of the output stage on the radiator, it is necessary to remember the need for thermal contact of the housings of pairs of transistors VT9, VT14 and VT10, VT13.

Other payments are separated with the help of the Sprint Layout 6 program, which allows you to customize the placement of payment elements, then. adapt the housing to a specific configuration. archives below.

Details of the support

The parameters of the power supply depend on the content of the stacked radio elements and their placement on the board. Stacked circuit solutions allow you to do without selecting a transistor, but instead just put in transistors with a cut-off amplification frequency of 5 to 200 MHz and a supply of cut-off operating voltage of more than 2 times the same with the tension of the cascade.

Since it is important and possible, it is important to choose transistors based on the principle of “complementarity” and the best characteristics. We tried preparation options with and without a selection of transistors. The option with selected “complementary” transistors shows significantly better characteristics, without any selection. Only KT940 and KT9115 with high-quality transistors are complementary, and in others the complementarity is reasonable. There are a lot of foreign transistors of complementary pairs, and information about this can be obtained from manufacturers’ websites and from distributors.

Like VT1, VT3, VT5 it is possible to install transistors of the KT3107 series with any letters. Like VT2, VT4, VT6, it is possible to use transistors of the KT3102 series with letters, which may have similar characteristics to static transistors for a different sound signal. It is possible to select transistors according to the parameters, it is better to work out the price. I can use all current testers without any problems. With great inspiration, the time spent on training will be greater and the result will be more modest. For VT6, transistors KT9115A, KP960A are used, and for VT7 - KT940A, KP959A.

Like VT9 and VT12 you can install transistors KT817V (G), KT850A, and like VT10 and VT11 - KT816V (G), KT851A. For VT13, transistors KT818V(G), KP964A are used, and for VT14 - KT819V(G), KP954A. Instead of zener diodes VD3 and VD4, you can use two series-connected AL307 LEDs or the like.

The circuit allows you to freeze other parts, otherwise correction of other boards may be necessary. Capacitor C1 can have a capacity of 1 to 4.7 µF µF and is made of polypropylene or something else, or clear. On the websites of radio amateurs you can find about this information. The connection of the life voltage, input and output signals is carried out using vicary terminals for manual installation.

The benefit of the podsiluvach

When you turn on the ULF for the first time, connect it through tight ceramic resistors (10 – 100 Ohms). There are many elements that need to be re-engineered and come out of order during installation. On the first part of the board, resistor R23 is installed with a quiet ULF (150-250 mA) when the voltage is turned on. Next, you need to establish the constant voltage at the output of the booster when the voltage equivalent is connected. It is necessary to change the value of one of the resistors R19 or R20.

After installing the circuit, set resistor R14 to the middle position. At the equivalent of the voltage, the presence of the booster is checked and resistor R5 is used to set the constant voltage at the output of the booster. The boost can be adjusted in static mode.

To operate in dynamic mode, the last lance R is connected in parallel with the vantage equivalent. A resistor with a weight of 0.125 W and a nominal value of 1.3-4.7 kOhm. Non-polar capacitor 1-2 uF. In parallel, a microammeter (20-100 µA) is connected to the capacitor. Then, having applied a sinusoidal signal with a frequency of 5-8 kHz to the booster input, using an oscillograph and a voltmeter connected to the output, you need to estimate the threshold level of booster intensity. After this, we reduce the input signal to the level of 0.7 volts and resistor R14 to achieve a minimum reading of the microammeter. In such cases, to reduce distortion at high frequencies, it is necessary to correct the forward phase by installing capacitor C12 (0.02-0.033 µF).

Capacitors C8 and C9 are selected for the shortest transmission of a pulse signal with a frequency of 20 kHz (installed if necessary). Capacitor C10 cannot be installed because the circuit is static. By changing the value of resistor R15, however, you can set the maximum strength for the skin channel in the stereophonic or multi-channel version. By changing the value of the quiet current of the output stage, you can try to find the highest linear operating mode.

Sound rating

The sound is even more harmonious. Do not elevate the listener's audition to "second". Of course, this is more likely to be reinforced, but due to the increased costs and losses, the scheme is likely to be rich. With clearer details and their selection, even more significant results can be achieved.

Posilannya and files

1. Korol V., “UMZCH with compensation for nonlinearity of amplitude characteristics” - Radio, 1989 No. 12, p. 52-54.

06/09/2017 - The scheme has been corrected, all archives have been re-uploaded.
▼ 🕗 09/06/17 ⚖️ 24.43 Kb ⇣ 17 Hello, reader! My name is Igor, I’m 45, I’m a Siberian and an avid electronics enthusiast. I discovered, created and lost this wonderful site in 2006.
For almost 10 years now, our magazine has been paying for my money.

Garnius! The freebie is gone. If you want files and beautiful statistics, help me!

The promotion of your dear respect is simple when formed, terribly simple when trained (it actually does not matter), do not place particularly deficient components and in this case there may be even worse characteristics and easy craving for such ranks hi-fi, so gently humming to most people.The power supply can be used for 4 and 8 ohm voltage, or you can substitute a bridge switched for 8 ohm voltage, which will result in 200 watts for the generator.

Main characteristics:

Live voltage, V................................................... ............... ±35
Strum, which lives in the washing mode, mA.................................. 100
Input information, to whom .................................................... .......... 24
Sensitivity (100 W, 8 Ohm), V.................................... ............. ...... 1.2
Output pressure (KG=0.04%), W...................................... ........ 80
Range of operating frequencies, Hz.................................. 10 - 30000
Signal/noise ratio (not important), dB..................... -73

I rely on discrete elements, without any op-amps or other tricks. For an hour of operation at a voltage of 4 Ohms and a live 35 V, the power supply develops up to 100 W. If there is a need to connect the voltage, the 8 Ohm voltage can be increased to +/-42 V, at which point we draw the same 100 W.It is not recommended to increase the voltage above 42, otherwise you may lose the output transistors. When operating in bridge mode, the 8-ohm bias may be compromised, otherwise, again, all hope for the survival of the output transistors is lost. Before speaking, we need to ensure that protection from the short circuit has not been transferred to the woman, so we need to be careful.To operate a power booster in bridge mode, you must connect the MT input to the output of another booster, to which input a signal is sent. The input that is lost is short-circuited to the ground wire. Resistor R11 serves to keep the output transistors quiet. Capacitor C4 signifies the upper limit of strength and change it without warning - eliminate self-excitation at high frequencies.
All resistors are 0.25 W behind R18, R12, R13, R16, R17. The first three are 0.5 W, the remaining two are 5 W each. The HL1 LED is not used for decoration; there is no need to build a bright diode into the circuit and display it on the front panel. The LED is primarily to blame for the green color - however, it is important that the fragments of the LED of other colors may cause a different voltage drop.If anyone was not spared and could not find the output transistors MJL4281 and MJL4302, they can be replaced with MJL21193 and MJL21194 in the same way.The replacement resistor R11 is better to take a high-turn resistor, although it is suitable and primary. There is nothing critical here - it’s just easier to keep things calm.

The simplest booster on transistors can be a good companion for the development of power devices. The circuits and designs are simple; you can independently prepare the device and test its operation, working with all the parameters. Zavdyaki suchasnym let's use transistors You can literally make a miniature microphone booster from just three elements. І connect it to a personal computer to reduce sound recording parameters. The same spіvrozmovniks under the hour of growth will be richer and clearer than your prom.

Frequency characteristics

Low (sound) frequencies are present in almost all everyday devices - music centers, televisions, radios, tape recorders and personal computers. There are also HF boosters on transistors, lamps and microcircuits. The beauty is that the ULF allows you to amplify a signal below the sound frequency that is perceived by the human ear. Adding force to sound transistors allow you to generate signals with frequencies ranging from 20 Hz to 20,000 Hz.

Then, use the simplest device to amplify the signal in this range. Moreover, it should be done as evenly as possible. The strength coefficient depends on the frequency of the input signal. The graph of the occurrence of these quantities is practically a straight line. As soon as a signal with a frequency range is applied to the input of the booster, the efficiency of the robot and the efficiency of the device will change rapidly. ULF cascades are, as a rule, assembled on transistors that operate in the low-mid-frequency ranges.

Class robots of sound boosters

All booster devices are divided into a number of classes, depending on what stage the process flows through the cascade:

1. Class “A” - the stream flows continuously throughout the entire period of operation of the power cascade.
2. In class “B” the flow lasts for half a period.
3. Class "AB" refers to those whose flow flows through the booster cascade for an hour, which is equal to 50-100% of the period.
4. In mode “C” the electric current flows less than half the time of operation.
5. Mode “D” ULF has become stagnant in amateur radio practice quite recently – just over 50 years ago. Most often, these devices are implemented with the protection of digital elements and have a very high efficiency factor - over 90%.

The presence of problems in different classes of low-frequency boosters

The operating area of ​​a class “A” transistor booster is characterized by very few nonlinear effects. Since the input signal generates pulses with a high voltage, this causes the transistors to become saturated. The output signal of the skin harmonics begins to appear (until 10-11). Through this, a metallic sound appears, characteristic of transistor boosters.

In case of unstable life, the output signal has a modeled amplitude relative to the frequency of the threshold. The sound on the left side of the frequency response becomes harsher. Apart from shortening the stabilization of the vitality of the booster, the design of the entire device becomes complex. ULF, which is used in class “A”, has a remarkably low CCD – less than 20%. The reason is that the transistor is constantly open and flows through it steadily.

For advancement (albeit insignificant) the QCD can be accelerated by push-pull circuits. One drawback is that the lines at the output signal become asymmetrical. If you transfer from class “A” to “AB”, non-linear problems increase 3-4 times. But the coefficient of corrosive action in all schemes will still increase. ULF classes “AB” and “B” characterize the increase in noise when the level of the input signal changes. It’s better to add thickness, but it won’t help to avoid any shortages.

Work in intermediate classes

There are a number of different types of skin. For example, the robot class is “A+”. The new transistor at the input (low voltage) is designated as “A”. Any high-voltage voltages that are installed at the output stages are placed either in “B” or “AB”. Such power plants are richly economical and are not in the “A” class. There are noticeably fewer nonlinear problems - no more than 0.003%. You can achieve even better results by vikory bipolar transistors. The operating principle behind these elements will be discussed below.

But all the same, there is a large number of high harmonics in the output signal, through which the sound becomes characteristic metal. There are also schemes of support workers that work in the “AA” class. The smell of non-linear components is even less - up to 0.0005%. All the same, the main feature of transistor boosters is the characteristic metallic sound.

"Alternative" designs

It’s impossible to say that they are alternative, but the fachists who are engaged in the design and selection of boosters for the clear creation of sound are increasingly giving priority to tube designs. Tube boosters have the following advantages:

1. The level of nonlinear effects on the output signal is even lower.
2. There are fewer harmonics in transistor designs.

However, there is one great minus that outweighs all the advantages - it is absolutely necessary to install devices for this purpose. On the right, the tube cascade has a very high reference value - several thousand ohms. The input of the speaker windings is 8 or 4 ohms. To please them, it is necessary to install a transformer.

Of course, this is not a great shortcoming - there are also transistor devices that use transformers to serve the output stage and acoustic system. Some experts confirm that the most effective scheme is a hybrid one - in which single-cycle boosters are combined, as long as they are not affected by negative feedback. Moreover, all these cascades function as ULF class “A”. In other words, it stagnates like a repeat of the pressure boost on the transistor.

Moreover, the CCD of such devices is high - close to 50%. It’s not easy to focus more on the performance of KKD and tension - let’s not even talk about the high intensity of the sound created by the force. Of much greater importance are the linearity of the characteristics and their brightness. Therefore, it is necessary to show respect to us in advance of them, and not to push.

Circuit of a single-ended ULF transistor

The simplest booster, based on the scheme with a carbon emitter, is in class “A”. The vikorist circuit has a conductor element with an n-p-n structure. The collector lancet has a support R3 installed, which encloses the flow that is leaking. The collector connector connects to the positive life wire, and the emitter connects to the negative wire. If there is a combination of feeder transistors with a pnp structure, the circuit will be the same, the axis will only need to change the polarity.

With the help of a separate capacitor C1, it is possible to boost the input variable signal from the device postynogo strum. In this case, the condenser is not suitable for passing the exchange stream through the base-emitter path. The internal support for the emitter-base junction together with resistors R1 and R2 is the simplest voltage distributor. Consider resistor R2 to be 1-1.5 kom - the highest typical value for such circuits. With such tension, life continues to flow steadily. If you power the circuit with a voltage of 20 Volts, then you can calculate that the value of the power factor of the strum h21 stock is 150. It is necessary to determine whether the booster HF on the transistors is connected to similar circuits, only do a little differently.

In this case, the voltage of the emitter is higher than 9 and the drop on the “E-B” line is 0.7 V (which is typical for transistors on silicon crystals). If we look at the booster on germanium transistors, then in this case the voltage drop on the “E-B” section is more than 0.3 V. The flow at the collector end is more similar to what flows in the emitter. You can calculate it by dividing the voltage of the emitter on the support R2 - 9V/1 kOhm=9 mA. To calculate the value of the base stream, 9 mA is required to divide the gain factor h21 - 9 mA/150 = 60 μA. In ULF designs, bipolar transistors are used. The principle of work differs from that of the field.

On resistor R1 you can now calculate the drop value - the difference between the base voltage and life. The basis voltage can be explained by the formula - the sum of the indicators of the emitter and the “E-B” transition. With a live voltage of 20 Volts: 20 - 9.7 = 10.3. You can calculate the value of the support R1 = 10.3 V/60 μA = 172 kOhm. The circuit has a C2 capacity, which is necessary for the implementation of the Lancug, where possible the exchangeable storage of the ether flow can take place.

If you do not install capacitor C2, the storage area will no longer be separated. Through this, such an increase in the sound on the transistors will result in a very low amplification factor along the h21 string. It is important to remember that the visceral organs were caught by the equal jets of the base and collector. Moreover, take the stream of the base with the one that flows from the lancug out of the emitter. The fault lies mainly in the supply of voltage to the base of the transistor.

But it is necessary to ensure that along the base lancet absolutely immediately, regardless of the obvious leakage, the flow of the manifold flows obligingly. In circuits with a carbon emitter, the current flow increases at least 150 times. In addition, this value is also insured for the expansion of boosters on Germanium transistors. In some cases, the vicor of silicon, in some strumas, the K-B lancet is even small, these values ​​simply do not matter.

Substation on MOS transistors

The modification on field-effect transistors, represented on the circuit, has many analogues. Including and with vikoristannyam bipolar transistors. This can be considered as a similar butt with a sound-enhancing design assembled behind a circuit with a carbon emitter. The photo shows a diagram, vikonana by diagram, with a zagalny dzherel. R-C connections are assembled on the input and output lances so that the device operates in class “A” booster mode.

The alternating current from the cylinder to the signal is reinforced by the constant voltage of the capacitor C1. Obviously, the boost on field-effect transistors is due to the gate potential, which is lower for the same characteristic as the turn. In the diagram, the gate is connected to the igniter behind an additional resistor R1. This is a very great idea - expect 100-1000 kOhm resistors in designs. Such a large reference is chosen so that the signal is not shunted at the input.

This operation does not allow an electric current to pass through, as a result of which the potential of the gate (if there is a signal at the input) is the same as that of the ground. At first, the potential appears higher, lower near the ground, only because of the voltage drop on support R2. It is clear that the shutter has low potential, low on the cob. This itself is necessary for the normal functioning of the transistor. It is necessary to pay attention to those that C2 and R3 in this power supply circuit have the same significance as in the considered structure. And the input signal is disrupted by 180 degrees before the output signal.

ULF from a transformer at the output

You can make such a booster with your own hands for your home wiki. It follows the scheme that works in class “A”. The design is the same as in the above-mentioned objects - from a carbon emitter. One feature is that you need to change the transformer to make it work. There is not much of a similar boost to the sound on transistors.

The collector circuit of the transistor is connected to the primary winding, which develops an output signal that is transmitted through the secondary dynamics. On resistors R1 and R3 there is a voltage divider, which allows you to select the operating point of the transistor. This lanyard will ensure the supply of displacement voltage to the base. All other components have the same meanings as in the above-mentioned circuits.

Push-pull sound booster

It is impossible to say that this is a simple booster on transistors, the fragments of this robot are a little foldable, below those looked at earlier. For push-pull ULFs, the input signal is split into two phases, different in phase. And the skin of this type will be powered by its cascade, viconim on a transistor. After the skin tension has increased, the offensive signals are connected and sent to the speakers. Such complex transformations of the building will respond to the signal, the fragments of the dynamic and frequency power of the two, but on the circuit board, the transistors will be identical.

As a result, the sound brilliance at the output of the booster is significantly reduced. During the operation of the push-pull booster in class “A”, it is impossible to clearly generate a folding signal. The reason is that the movement of the struma flows through the shoulders steadily, asymmetrically, phases of co-operation occur. The sound becomes less intelligible, and when the signal is heated, it becomes even stronger, especially at low and super-low frequencies.

Transformerless ULF

Low-frequency booster on a transistor, vikonaniy with a transformer, regardless of the fact that the design can be of small dimensions, is still not thorough. Transformers are still important and bulky, so it’s better to worry about them. A highly effective circuit is based on complementary conductor elements with different types of conductivity. Most current ULFs follow such circuits and belong to class “B”.

Two hard transistors, which are used in the design, work behind the emitter repeater circuit (field collector). With this voltage, the input is transferred to the output without loss of power. If there is no signal at the input, the transistors are between switched on and still switched on. When a harmonic signal is applied to the input, the positive voltage of the first transistor is activated, and the other one is in the counter mode at that time.

Well, it’s too positive to go through this building. Otherwise, the other transistor is turned on negatively and the first one is completely short-circuited. In this case, more negative feelings are revealed in the obsessed ones. As a result of tightening, the signal appears at the output of the device. Such a transistor boost circuit is very effective and ensures stable operation, clearly related to sound.

ULF circuit on one transistor

Having taken into account all the features described above, you can assemble a booster with your own hands on a simple elemental basis. The transistor can be purchased from the KT315 or any foreign analogue - for example, the BC107. For reasons of convenience, it is necessary to use headphones based on 2000-3000 Ohms. A voltage must be applied to the base of the transistor through a resistor with a 1 MΩ support and a decoupling capacitor of 10 μF. Live circuits can be created with a voltage of 4.5-9 Volts, a voltage of 0.3-0.5 A.

If support R1 is not connected, then there will be no stream in the base and collector. However, when the voltage is connected, it reaches a level of 0.7 and allows a flow of about 4 µA. In this case, the power factor appears to be close to 250. From this, you can perform a simple expansion of the booster on the transistors and find out about the collector flow - it turns out to be as high as 1 mA. Having collected this booster circuit on a transistor, you can carry out its verification. Before exiting, connect your headphones.

If you press your finger, a characteristic noise will appear. If it is missing, then, most likely, the design is assembled incorrectly. Check all the connections and the values ​​of the elements. To start the demonstration, connect the audio output to the ULF input of the player or phone. Listen to the music and appreciate the richness of the sound.