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Headlamp wiring diagram. A few simple LED power circuits

At present, power outages have become very frequent, therefore, in amateur radio literature, a lot of attention is paid to local power sources. Not very energy-intensive, but very useful during emergency shutdowns, is a compact rechargeable flashlight (AKF), in the battery (battery) of which three sealed disk nickel-cadmium batteries D 0.25 are used. The failure of the ACF for one reason or another causes considerable grief. However, if you apply a little ingenuity, understand the design of the flashlight itself and know elementary electrical engineering, then it can be repaired, and the little friend will serve for a long time and reliably.

Circuit design. Design

Let's start, as expected, with a study of the instruction manual 2.424.005 R3 Battery lamp "Electronics V6-05". Inconsistencies begin immediately after a careful comparison of the electrical circuit diagram (Fig. 1) and the design of the flashlight. In the circuit, the plus is from the battery, and the minus is connected to the HL1 light bulb.

In reality, the coaxial output HL1 is constantly connected to the plus of the battery, and the minus is connected through S1 to the threaded base. Having carefully examined the mounting connections, we immediately notice that HL1 is not connected according to the scheme, the capacitor C1 is connected not to VD1 and VD2, as shown in Fig. 1, but to the elastic contact of the structure, which presses the battery minus, which is structurally and technologically convenient, since C1, as the most overall element, it is rather rigidly mounted with structural elements - one of the pins of the mains plug, structurally integrated with the ACF case and the battery spring contact; resistor R2 is not connected in series with capacitor C1, but is soldered at one end to the second pin of the mains plug, and at the other end to the holder. U1. This is also not taken into account in the ACF scheme in . The remaining connections correspond to the diagram shown in Fig.2.

But if you do not take into account the design and technological advantages, which are quite obvious, then in principle it does not matter how C1 is connected, according to Fig. 1 or Fig. 2. By the way, with a good idea to refine the circuit of the charger (charger) of the ACF, it was not possible to avoid the use of "extra" elements.

The memory circuit, while maintaining the general algorithm, can be significantly simplified by assembling it according to Fig. 3.

The difference lies in the fact that the elements VD1 and VD2 in the diagram in Fig. 3 perform two functions each, which made it possible to reduce the number of elements. The zener diode VD1 for the negative half-wave of the supply voltage to VD1, VD2 serves as a rectifier diode, it is also a source of positive reference voltage for the comparison circuit (CC), the (second) function of which is also performed by VD2. CC works as follows: when the value of the EMF at the VD2 cathode is less than the voltage at its anode, the battery is being charged normally. As the charge increases, the EMF value on the battery increases, and when it reaches the anode voltage, VD2 will close and the charge will stop. The value of the reference voltage VD1 (stabilization voltage) should be equal to the sum of the voltage drop in the forward direction on VD2 + the voltage drop on R3VD3 + EMF of the battery and is selected for a specific charge current and specific elements. The emf of a fully charged disk is 1.35 V.

With such a charge scheme, the LED as an indicator of the state of charge of the battery at the beginning of the process lights up brightly, as it charges, its brightness decreases, and when it reaches full charge, it goes out. If during operation it is noticed that the product of the charge current and the VD3 glow time in hours is much less than its theoretical capacity, then this does not mean that the comparator on VD2 is not working correctly, but that one or more disks have insufficient capacity.

Operating conditions

Now let's analyze the charge and discharge of the battery. According to TU (12MO.081.045), the charging time for a fully discharged battery at a voltage of 220 V is 20 hours. The charging current at C1 \u003d 0.5 μF, taking into account the variation in capacitance and fluctuations in the magnitude of the supply voltage, is about 25-28 mA, which corresponds to the recommendations, and the recommended discharge current is twice the charge current, i.e. fifty

ma. The number of complete charge-discharge cycles is 392. In the real design of the ACF, the discharge is carried out on a standard bulb of 3.5 V x 0.15 A (with three disks), although it gives an increase in brightness, but also due to an increase in the current from the battery in excess of that recommended by the specifications , negatively affects the battery life, therefore, such a replacement is hardly advisable, since in some copies of the disks this can cause increased gas formation, which in turn will lead to an increase in pressure inside the case and to a deterioration in the internal contact made by the Belleville spring between the tablet package active substance and the negative part of the housing. This also leads to the release of electrolyte through the seal, which causes corrosion and the associated deterioration of contact both between the disks themselves and between the disks and metal elements of the ACF structure.

In addition, due to leaks, water evaporates from the electrolyte, as a result of which the internal resistance of the disk and the entire battery increases. With further operation of such a disk, it fails completely as a result of the transformation of the electrolyte partly into crystalline KOH, partly into K2CO3 potash. It is for these reasons that charge-discharge issues need to be given special attention.

Practical repair

So, one of the three batteries "has gone wrong". You can assess its condition with an avometer. Why (in the appropriate polarity) briefly close each disk with the probes of an avometer set to measure direct current in the range of 2-2.5 A.

For good, freshly charged disks, the short circuit current should be within 2-3 A. When repairing an ACF, two logical options may arise: 1) there are no spare disks; 2) there are spare disks.

In the first case, this solution will be the simplest. Instead of the third, unusable disk, a washer is installed from the copper case of an unusable transistor of the KT802 type, which, moreover, fits well into most ACF designs in terms of dimensions. To make the washer, the leads of the transistor electrodes are removed and both ends are cleaned with a fine file from the coating until copper appears, then they are ground on fine-grained sanding paper laid on a flat plane, after which they are polished to a shine on a piece of felt with a layer of GOI paste applied. All these operations are necessary to reduce the effect of contact resistance on the burning time. The same applies to the contact ends of the disks, the darkened surfaces of which during operation are desirable for the same reasons to be reground.

Since the removal of one disk will lead to a decrease in the brightness of the HL1 glow, then a 2.5 V bulb at 0.15 A is installed in the ACF, or, even better, a 2.5 V bulb at 0.068 A, which, although it has less power, however, a decrease in current discharge allows you to bring it closer to the recommended according to specifications, which will favorably affect the life of the battery disks. Practical disassembly and analysis of correctable causes of disc failure showed that quite often the cause of inoperability is the destruction of the Belleville spring. Therefore, do not rush to throw away an unusable disk and, if you're lucky, you can make it work some more. This operation will require sufficient accuracy and certain locksmith skills.

To carry it out, you will need a small bench vise, a ball from a ball bearing with a diameter of about 10 mm and a smooth steel plate 3-4 mm thick. The plate is placed through a pad of 1 mm thick electric cardboard between the jaws and the positive part of the body, and the ball is placed between the second jaw and the negative part of the body, orienting the ball approximately in its center. The gasket made of electric cardboard is designed to eliminate the short circuit of the disk, and the plate is designed to evenly distribute the force and prevent deformation of the positive part of the battery case from notches on the vise jaws. Their dimensions are obvious. Gradually close the vise. Having pressed the ball by 1-2 mm, the disk is removed from the device and the short-circuit current is controlled. Usually, after one or two clamps, more than half of the charged disks begin to show an increase in short-circuit current up to 2-2.5 A. After a certain amount of stroke, the clamping force increases sharply, which means that the deformable part of the case rests on the tablet. Further clamping is impractical, as it leads to the destruction of the battery. If, after the stop, the short-circuit current does not increase, then the disk is completely unusable.

In the second case, simply replacing a disk with another one may also not bring the desired result, since fully functional disks have a so-called "capacitive" memory.

Due to the fact that during operation, the battery always has at least one disk that has a lower capacity value, which is why when it is discharged, the internal resistance sharply increases, which limits the possibility of a complete discharge of the remaining disks. It is not advisable to subject such a battery to some overcharging to eliminate this phenomenon, since this will not lead to an increase in capacity, but only to the failure of the best disks. Therefore, when replacing at least one disk in the battery, it is advisable to subject them all to forced training (give one full charge-discharge cycle) to eliminate the above phenomena. The charge of each disk is carried out in the same ACF, using transistor washers instead of two disks.

The discharge is carried out on a resistor with a resistance of 50 ohms, providing a discharge current of 25 mA (which corresponds to specifications), until the voltage across it reaches 1 V. After that, the disks are put into a battery and charged together. After charging the entire battery, they discharge it to the standard HL until the battery reaches 3 V. Under the load of the same HL, the short-circuit current of each disk discharged to 1 V is checked again.

For disks suitable for operation as part of a battery, the short-circuit current of each disk should be approximately the same. The battery capacity can be considered sufficient for practical use if the discharge time to 3 V is 30-40 minutes.

Details

Fuse.U1. Observing the evolution of ACF circuitry for about two decades during repairs, it was noticed that in the mid-80s, some enterprises began to produce batteries without fuses with a current-limiting resistor of 0.5 W and a resistance of 150-180 Ohm, which is quite justified, since during a breakdown C1 played the role of U1 R2 (Fig. 1) or R2 (Fig. 2 and 3), the conductive layer of which evaporated much earlier (than U1 burned out by 0.15 A), interrupting the circuit, which is required from the fuse. Practice confirms that if a current-limiting resistor with a power of 0.5 W in a real ACF circuit noticeably heats up, then this clearly indicates a significant leakage of C1 (which is difficult to determine with an avometer, and also due to a change in its value over time), and it must be replaced .

Capacitor C1 type MBM 0.5 uF at 250 V is the most unreliable element. It is designed for use in DC circuits with the appropriate voltage, and the use of such capacitors in AC networks, when the voltage amplitude in the network can reach 350 V, and taking into account the presence of numerous peaks from inductive loads in the network, as well as the charging time of a fully discharged ACF according to specifications (about 20 hours), then its reliability as a radio element becomes very small. The most reliable capacitor, which has optimal dimensions that allow it to fit into ACFs of various design sizes, is the K42U-2 capacitor 0.22 μF H 630 V or even K42U 0.1 μF H 630 V. Reducing the charging current to about 15-18 mA, at 0.22 uF and up to 8-10 mA at 0.1 uF practically only causes an increase in its charge time, which is not significant.

Charging current LED indicator VD3. In ACFs that do not have an LED charge current indicator, it can be installed by connecting it to the circuit break at point A (Fig. 2).

The LED is connected in parallel with the measuring resistor R3 (Fig. 4), which must be selected for new manufacture or reduction of C1. With a capacitance C1 equal to 0.22 uF, instead of 0.5 uF, the brightness of VD3 will decrease, and at 0.1 uF, VD3 may not light up at all. Therefore, taking into account the above charge currents, in the first case, the resistor R3 must be increased proportionally to the decrease in current, and in the second case it must be removed completely. In practice, taking into account the fact that it is very unsafe to work with 220 V, it is better to select the resistance R3 by connecting an adjustable DC source (RIPT) through a milliammeter to point B (Fig. 3) and controlling the charge current. Instead of R3, a potentiometer with a resistance of 1 kΩ is temporarily connected, turned on by a rheostat to the minimum resistance. By increasing the RIPT voltage, the battery charge current is set to 25 mA.

Without changing the set voltage of the RIPT, turn on the milliammeter to open the VD3 circuit at point C and, gradually increasing the resistance of the potentiometer, achieve a current of 10 mA through it, i.e. half of the maximum for AL307. This moment is especially important for circuits without a zener diode, in which, at the first moment after turning on when charging C1, the current through VD3 can become large, despite the presence of a current-limiting resistor R1, and can lead to VD3 failure. In the steady state, R1 has practically no effect on the charge current due to its low resistance compared to the reactive (about 9 kOhm) resistance C1. When finalizing VD3, they are installed in a hole with a diameter of 5 mm, drilled symmetrically to the connector line in the housing between the supports of the spring contact connected to the HL1 coaxial output, and the battery plus. The measuring resistor is placed in the same place.

Rectifier Diodes

Given the presence of a current surge at the initial charge of C1, to increase the reliability in the ACF rectifier, it is desirable to use any silicon pulse diodes with a reverse voltage of 30 V.

Non-standard application of ACF

Having made an adapter from the base of a worthless light bulb and the power connector of the radio receiver, the ACF can be used not only as a source of light, but also as a source of secondary power supply with a voltage of 3.75 V. At an average volume level (current consumption of 20-25 mA), its capacity is quite enough for listening to the WEF for several hours.

In some cases, in the absence of electricity, the ACF can also be recharged from a radio transmission line. AKF owners with LED indicator can observe the process of dynamic blinking of the LED. Especially exactly VD3 burns from "heavy" rock, so if you don't like to listen - charge the AKF, use the energy for peaceful purposes. The physical meaning of this phenomenon is to reduce the reactance with increasing frequency, therefore, at a much lower voltage (15-30 V), the pulse value of the charge current through the indicator is sufficient for its glow and, of course, recharging.

Literature:

Vuzetsky V.N. Charger for a rechargeable flashlight // Radioamator.- 1997.- No. 10.- P.24.
Tereshchuk R.M. etc. Semiconductor receiving-amplifying devices: Ref. radio amateur. - Kyiv: Nauk. thought, 1988

Read and write useful

Many have various Chinese lanterns powered by a single battery. Like this:

Unfortunately, they are very short lived. About how to bring the flashlight back to life and about some simple improvements that can improve such flashlights - I'll tell you later.

The weakest point of such lamps is the button. Her contacts are oxidized, as a result of which the flashlight starts to shine dimly, and then it may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines weakly, but if you click the button several times, the brightness increases.
The easiest way to make such a flashlight shine is to do the following:

1. We take a thin stranded wire, cut off one vein.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the swirling part of the flashlight.
4. Tighten tightly. We break off the excess wire (tear off).
As a result, the wire makes good contact with the negative side of the battery and the flashlight.
shine with proper brightness. Of course, the button with such a repair remains out of place, therefore
Turning the flashlight on and off is done by turning the head.
My Chinese worked like that for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our heads away.

RESTORING THE FUNCTIONALITY OF THE BUTTON.

Today I decided to bring the button back to life. The button is in a plastic case, which
It's just pressed into the back of the headlight. In principle, it can be pushed back, but I did it a little differently:

1. We make a pair of holes with a 2 mm drill to a depth of 2-3 mm.
2. Now you can unscrew the case with the button with tweezers.
3. Remove the button.
4. The button is assembled without glue and latches, so it is easy to disassemble it with a clerical knife.
The photo shows that the movable contact has oxidized (a round garbage in the center, similar to a button).
It can be cleaned with an eraser or fine sandpaper and assemble the button back, but I decided to additionally irradiate this part and the fixed contacts.

1. We clean with a fine sandpaper.
2. We serve with a thin layer of places marked in red. We wipe with alcohol from the flux,
collect the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. We collect everything back.
After repair, the button works fine. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. Not without reason, on light bulbs, the central contact is made of tin.

IMPROVE FOCUSING.

What is a "hotspot", my Chinese had a very vague idea, so I decided to enlighten him.
Unscrew the head.

1. There is a small hole in the board (arrow). Using an awl, twist the filling,
at the same time lightly press your finger on the glass from the outside. This makes it easier to roll out.
2. Remove the reflector.
3. We take ordinary office paper, punch 6-8 holes with an office hole punch.
The diameter of the holes of the hole punch perfectly matches the diameter of the LED.
Cut out 6-8 paper washers.
4. We put the washers on the LED and press it with a reflector.
Here you have to experiment with the number of pucks. I improved the focus of a pair of flashlights in this way, the number of washers was in the range of 4-6. On the current patient, it took 6.
What happened in the end:

On the left - our Chinese, on the right - Fenix LD 10 (at a minimum).
The result is quite pleasant. Hotspot became pronounced and uniform.

INCREASING THE BRIGHTNESS (for those who are a little versed in electronics).

The Chinese save on everything. A couple of extra details - an increase in cost, so they don’t put it.

The main part of the circuit (marked in green) can be different. On one or two transistors or on a specialized microcircuit (I have a two-part circuit:
choke and a 3-leg microcircuit similar to a transistor). But on the part marked in red - they save. I added a capacitor and a couple of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.

1. This is how the LED looks like in similar Chinese. From the side you can see that there are thick and thin legs inside. The thin leg is a plus. You need to navigate by this sign, because the colors of the wires can be completely unpredictable.
2. This is how the board to which the LED is soldered looks like (on the reverse side). Foil is marked in green. The wires coming from the driver are soldered to the legs of the LED.
3. With a sharp knife or a triangular file, cut the foil on the plus side of the LED.
We sand the entire board to remove varnish.
4. Solder the diodes and the capacitor. I took the diodes from a broken computer power supply, and soldered a tantalum capacitor from some burnt hard drive.
The positive wire now needs to be soldered to the pad with diodes.

As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the phoenix, which in the minimum mode produces 9 lumens.

And the last: the advantage of the Chinese over the branded flashlight (yes, don't laugh)
Branded flashlights are designed to use batteries, so
with the battery down to 1 volt, my Fenix LD 10 simply won't turn on. At all.
I took a dead alkaline battery that had served its time in a computer mouse. The multimeter showed that she sat down to 1.12v. The mouse no longer worked on it, Fenix, as I said, did not start. But the Chinese - it works!

Left - Chinese, right - Fenix LD 10 at a minimum (9 lumens). Unfortunately, the white balance is off.
Phoenix has a temperature of 4200K. The Chinese is blue, but not as bad as in the photo.
For the sake of interest, I tried to finish off the battery. At this level of brightness (5-6 lumens per eye), the flashlight worked for about 3 hours. Brightness is quite enough to illuminate under your feet in a dark entrance / forest / basement. Then for another 2 hours the brightness decreased to the level of a "firefly". Agree, 3-4 hours with acceptable light can solve a lot.
Let me take a bow for this.
Stari4ok.

Z.Y. The article is not a copy-paste. Made in me, especially for "NOT DISAPPEAR"!

The flashlight charger is not assembled well, by soldering the elements with leads to each other. When the flashlight falls, the elements of the charger dangle like pencils in a glass, which leads to the destruction of the charger circuit.

The charger consists of: capacitor, rectifier diodes, active resistance, LED for charge indication. The question arose of how to restore the charger circuit without having a passport for a flashlight and a wiring diagram. It's no joke, if you confuse something in the circuit, it's still included in the 220V network. Let's reason logically for each element in the flashlight, what the element is for and what function it performs.

What is alternating current? This is the directed movement of charged particles in a conductor with a frequency of 50 Hz. What is the current frequency of 50 Hz? This is the number of cycles in one second, changing the direction of the current, from positive to negative 50 times in one second.

How is alternating current obtained? It is the conversion of mechanical energy into electrical energy by means of generator. For simplicity and a clear example, consider the simplest generator, consisting of a two-pole magnet and one winding.

The chart shows one period, a negative moment and positive. In the figure we see two magnetic poles, and one generator winding in the form of a circle with a number. The figure shows the movement of the generator winding counterclockwise in eight steps. On the graph, the period begins with the number one and ends with the number eight, making a full 360 degree rotation.

The advantage of an alkaline battery over lead is its high mechanical and electrical strength: it withstands significant overloads and current fluctuations, is not afraid of overcharging and undercharging, can be inoperative for a long time and requires less maintenance.
Efficiency of alkaline batteries - 60%; lead batteries - 75%.

As for the acid battery: The charging current (in amp-hours) must not exceed the capacity of the battery (in amp-hours). For example, the maximum charging current for a battery with a capacity of 180 Ah is 18 A. (I=Q-/10). A normal battery charge usually lasts 12 hours. With a higher current, the battery overheats and the active mass of the plates is destroyed. If the charge is carried out with a lower current, which is quite acceptable and even desirable, then the duration of the charge increases accordingly.

Completion of the acid battery charging process characterized by the establishment of a voltage on one battery cell equal to 2.5 ... 2.6 V. Acid batteries are sensitive to undercharges and overcharges, so you should finish charging in a timely manner. Alkaline batteries are less critical to the operating mode. For them, the end of the charge is characterized by the establishment of a constant voltage of 1.4 ... 1.5 V on one battery cell.

Question: And how can I charge the battery to the flashlight using the AC-DC adapter?

Answer: Of course you can try. If the conditions are met: the battery voltage should be slightly less than the rated voltage of the charger. The consumed charging current must not exceed the rated charging current indicated on the charger. We observe the conditions for the polarity of the terminals during charging ("+" "-").

Question: Tell me why everything is battery. empty? After all, if you open any (remove the cork from the jar), it will be empty. Isn't this the reason for the short battery life? I somehow tried to fill in electrolyte with auto AB, and for more than 5 years my china has been shining.

Answer: Acid batteries are harmful due to their fumes. And empty batteries are hollow, that they are on a solid electrolyte, that is, impregnated, when completely dry, the battery stops working, it is enough to slightly soak it with distilled water, put it on charge and it will work.

Question: Please tell me how long it takes to charge a flashlight with such a battery so as not to overcharge. My battery has no markings. I only know the voltage of 3.6V, in the form of a 4-faceted white cup

Answer: To determine the charge current and charge time, you need to know the battery capacity (mA / h - milliamp / hour) For example, a 1000mA / h battery, let's supply a charge current of 100mA one tenth of the battery capacity, then it will charge in 10 hours. How to determine the approximate battery capacity? Simply by discharging it to the consumer knowing its current consumption. For example, we connect a load of 100mA, and after 10 hours the battery is completely discharged. We multiply the consumed current by the time, we get the battery capacity 100*10 = 1000mA/h.

Thank you! In the future, I will change the battery to 3 disk ones.

KD105A what can be replaced? You can replace diodes with KD105 (B, C, G); KD109V; D226A, almost any with a working current of 100 μA or more.

The parameters of the resistor R2 -22k are not basic, the voltage drop occurs due to the capacitor C1-1mkF, the resistance of which is approximately 2847 (Ohm), and R2 serves to protect the capacitor from breakdown. Resistor R1 serves to discharge capacitor C. When R1 is removed from the circuit, the charger will work, but when the flashlight is removed from the outlet, the capacitor will remain charged, and God forbid they touch the power plug, it will distort so that you can see the stars.

The charger will provide: charging current = 65 - 70 mA. voltage = 3.6 V.

Today we will talk about how to fix the LED Chinese flashlight yourself. We will also consider do-it-yourself LED lamp repair instructions with visual photos and videos.

As you can see, the scheme is simple. Main elements: current-limiting capacitor, rectifier diode bridge on four diodes, battery, switch, super-bright LEDs, flashlight battery charging indicator LED.

Well, now in order about the appointment of all the elements in the flashlight.

current limiting capacitor. It is designed to limit the battery charge current. Its capacity for each type of flashlight may be different. A non-polar mica capacitor is used. The operating voltage must be at least 250 volts. In the circuit, it must be shunted, as shown, by a resistor. It serves to discharge the capacitor after you unplug the flashlight from the charger from the outlet. Otherwise, you may be electrocuted if you accidentally touch the 220 volt power leads of the flashlight. The resistance of this resistor must be at least 500 kΩ.

The rectifier bridge is assembled on silicon diodes with a reverse voltage of at least 300 volts.

To indicate the charging of the flashlight battery, a simple red or green LED is used. It is connected in parallel with one of the rectifier bridge diodes. True, in the circuit, I forgot to specify the resistor connected in series with this LED.

It makes no sense to talk about the rest of the elements, so everything should be clear anyway.

I would like to draw your attention to the main points of the LED flashlight repair. Let's consider the main malfunctions and ways to eliminate them.

1. Flashlight stopped shining. There are not so many options here. The reason may be the failure of super-bright LEDs. This can happen, for example, in the following case. You put the flashlight on charge and accidentally turned on the switch. In this case, a sharp current surge will occur and one or more diodes of the rectifier bridge may be broken. And behind them, maybe the capacitor will not withstand and close. The voltage on the battery will rise sharply and the LEDs will fail. So in no case do not turn on the flashlight when charging, if you do not want to throw it away.

2. The flashlight does not turn on. Well, here you need to check the switch.

3. The flashlight runs out of power very quickly. If your flashlight is with “experience”, then most likely the battery has exhausted its service life. If you actively use the flashlight, then after one year of operation, the battery no longer holds.

Problem 1: LED flashlight does not turn on or flickers when working

As a rule, this is the cause of poor contact. The easiest way to treat is to tighten all threads tightly.
If the flashlight does not work at all, start by checking the battery. Maybe it's broken or out of order.

Unscrew the rear cover of the flashlight and use a screwdriver to close the case with the negative battery contact. If the flashlight lights up, then the problem is in the module with the button.

90% of the buttons of all LED lights are made according to the same scheme:
The body of the button is made of aluminum with a thread, a rubber cap is inserted there, then the button module itself and the clamping ring for contact with the body.

The problem is most often solved in a loose clamping ring.
To eliminate this malfunction, it is enough to find round-nose pliers with thin stings or thin scissors that need to be inserted into the holes, as in the photo, and rotated clockwise.

If the ring moves, then the problem is fixed. If the ring is in place, then the problem lies in the contact of the button module with the body. Unscrew the clamping ring counterclockwise and pull the button module out.
Often poor contact is due to oxidation of the aluminum surface of the ring or rim on the printed circuit board (indicated by arrows)

Simply wipe these surfaces with alcohol and the functionality will be restored.

Button modules are different. Some in which the contact goes through the printed circuit board, others in which the contact goes through the side lobes to the lamp body.
Just bend such a petal to the side so that the contact is tighter.
Alternatively, you can solder from tin so that the surface is thicker and the contact is pressed better.
All LED lights are basically the same.

Plus goes through the positive battery contact to the center of the LED module.
The minus goes through the case and closes with a button.

It will not be superfluous to check the fit of the LED module inside the case. This is also a common problem with LED lights.

Use round nose pliers or tongs to turn the module clockwise until it stops. Be careful, at this point it is easy to damage the LED.
These actions should be quite enough to restore the functionality of the LED flashlight.

It is worse when the flashlight works and the modes are switched, but the beam is very dim, or the flashlight does not work at all and there is a burning smell inside.

Problem 2. The flashlight works fine, but is dim or does not work at all and there is a burning smell inside

Most likely the driver has failed.
A driver is an electronic transistor circuit that controls the flashlight modes and is also responsible for a constant voltage level, regardless of the battery discharge.

You need to desolder the burnt driver and solder in a new driver, or connect the LED directly to the battery. In this case, you lose all modes and are left with only the maximum.

Sometimes (much less often) the LED fails.
You can check this very easily. bring a voltage of 4.2 V / to the contact pads of the LED. The main thing is not to reverse the polarity. If the LED is bright, then the driver is out of order, if vice versa, then you need to order a new LED.

Unscrew the LED module from the housing.
Modules are different, but as a rule, they are made of copper or brass and

The weakest point of such lamps is the button. Her contacts are oxidized, as a result of which the flashlight starts to shine dimly, and then it may stop turning on altogether.
The first sign is that a flashlight with a normal battery shines weakly, but if you click the button several times, the brightness increases.

The easiest way to make such a flashlight shine is to do the following:

1. We take a thin stranded wire, cut off one vein.
2. We wind the wires onto the spring.
3. We bend the wire so that the battery does not break it. The wire should protrude slightly
above the swirling part of the flashlight.
4. Tighten tightly. We break off the excess wire (tear off).
As a result, the wire makes good contact with the negative side of the battery and the flashlight.
shine with proper brightness. Of course, the button with such a repair remains out of place, therefore
turning on - turning off the flashlight is done by turning the head.
My Chinese worked like that for a couple of months. If you need to change the battery, the back of the flashlight
should not be touched. We turn our heads away.

RESTORING THE FUNCTIONALITY OF THE BUTTON.

1. We make a pair of holes with a 2 mm drill to a depth of 2-3 mm.
2. Now you can unscrew the case with the button with tweezers.
3. Remove the button.
4. The button is assembled without glue and latches, so it is easy to disassemble it with a clerical knife.
The photo shows that the movable contact has oxidized (a round garbage in the center, similar to a button).
It can be cleaned with an eraser or fine sandpaper and assemble the button back, but I decided to additionally irradiate this part and the fixed contacts.

1. We clean with a fine sandpaper.
2. We serve with a thin layer of places marked in red. We wipe with alcohol from the flux,
collect the button.
3. To increase reliability, I soldered a spring to the bottom contact of the button.
4. We collect everything back.
After repair, the button works fine. Of course, tin also oxidizes, but since tin is a fairly soft metal, I hope that the oxide film will be
easy to break down. Not without reason, on light bulbs, the central contact is made of tin.

IMPROVE FOCUSING.

What is a "hotspot", my Chinese had a very vague idea, so I decided to enlighten him.
Unscrew the head.

1. There is a small hole in the board (arrow). Using an awl, twist the filling,
at the same time lightly press your finger on the glass from the outside. This makes it easier to roll out.
2. Remove the reflector.
3. We take ordinary office paper, punch 6-8 holes with an office hole punch.
The diameter of the holes of the hole punch perfectly matches the diameter of the LED.
Cut out 6-8 paper washers.
4. We put the washers on the LED and press it with a reflector.
Here you have to experiment with the number of pucks. I improved the focus of a pair of flashlights in this way, the number of washers was in the range of 4-6. On the current patient, it took 6.

INCREASING THE BRIGHTNESS (for those who are a little versed in electronics).

The Chinese save on everything. A couple of extra details - an increase in the cost, so they do not put it.

The main part of the circuit (marked in green) can be different. On one or two transistors or on a specialized microcircuit (I have a two-part circuit:
choke and a 3-leg microcircuit similar to a transistor). But on the part marked in red - they save. I added a capacitor and a couple of 1n4148 diodes in parallel (I didn't have any shots). The brightness of the LED increased by 10-15 percent.

As a result, the flashlight produces (by eye) 10-12 lumens (see photo with hotspots),
judging by the phoenix, which in the minimum mode produces 9 lumens.

Good afternoon to all readers and admirers of the Radio Scheme site! Today I want to introduce you to another alteration of the Chinese lantern.

Once I got a plastic case of impressive size from some Chinese flashlight of an unknown company, completely free of charge. I decided that it would be useful - I'll do something. Having disassembled, I found inside a completely dead battery of an unknown manufacturer, there is not a single inscription on it. Light-emitting elements were also absent. Well, I postponed it until better times.

Battery replacement

Subsequently, a 6 volt 4.5 A / h battery of the same size was purchased. True, its size was a little larger, so the body had to be, as they say, “finish it with a file.”

At the top of the lantern, there was apparently some kind of incandescent bulb. After a little poking around with my brains and eyes in my bins, I found that in the place of the latter, a lens from a one-watt LED fits very well. Which, with the help of the same file, successfully fit into this technological hole, along with the same LED. And subsequently, two pieces of an aluminum profile from sliding furniture doors were glued to it, as a radiator. Initially, I wanted to put a three-watt LED there, but the experience of using such diodes said that my improvised radiator would not have enough cooling area (and a larger one would not fit inside the flashlight), so I decided to stop at a one-watt diode.

I wanted to power the LED using. But then a car charger for the phone came into hand, as it turned out, built on some Chinese analogue of the same MC34063, since the circuit coincided one to one. I decided to take this board as a basis, unsoldered the USB connector, replaced the voltage divider with a multi-turn tuning resistor. I set the current to 270 mA (while the diode is rated for 350 mA - there will be a margin). The power of light is quite enough to illuminate the space of 15-20 meters at night.

Installing LEDs

Further, at the bottom, most likely, there was some kind of fluorescent lamp. What can be determined by the characteristic protrusions on the reflector. Without hesitation, I decided to install LEDs there, which recently came from China:

Everything was done very simply. I marked the location of the LEDs on a checkered paper, glued it to the reflector with paper glue and drilled holes for the leads with a millimeter drill. I removed the paper, cleaned the reflector with a cloth from glue, inserted the LEDs and bent the legs. Since I did not want to sculpt the driver, I decided to limit myself to resistors. I connected the LEDs in parallel and put a 180 Ohm resistor on each LED, I used SMD resistors for this, which I melted directly into the plastic, since the battery turned out to be too big and there was simply no room for output elements.

The power switch is located at the top of the handle and has three fixed positions. In the middle position, everything is off, in the rearmost position, the lower part of the lamp is turned on, it gives diffused light. And in the extreme forward position, the upper part turns on and gives a narrowly directed beam of light, plus the lower part is powered to it through a diode soldered to the switch.

Voltage indicator

Then the idea arose to make an indication of the battery charge. I searched the internet and found this table:

Since I have a 6 volt battery, the numbers from the “voltage” column must be divided by two. I decided to assemble an indicator on the widespread LM324 chip, which is a quad operational amplifier (op-amp). Since I already soldered a similar circuit for the light indication of a metal detector, I still had a signet, which later had to be slightly modified. To display information about the battery status, I took four values \u200b\u200b(by the number of op-amps) - 20%, 40%, 60% and 80%. I had to kill half a day just to calculate the voltage divider, I even specially compiled a table in Excel for this, so that it would be easier to count.

I brought the indicator on button to the case under the handle, when you press it, the number of LEDs corresponding to the charge lights up. If one is on, then 20%, if all, then 80% or more.

power bank

The next function of my flashlight was the ability to charge mobile devices. Since the battery has a good capacity, it may well.

I thought for a long time about how to harmonize the voltage levels of the battery and the mobile phone. At first I wanted to make the same converter on the MC34063, but it did not fit because of the small voltage difference, there was an option to install the LM7805, but again it disappeared for the same reason. As a result, having talked on our forum with friends of radio amateurs (for which they thanks a lot!) came to the conclusion that it is possible to use an ordinary resistor that will limit the current, and by simple manipulations with Ohm's law, this element was calculated. It turned out 3 ohms 1 watt.

Charge indicator

Next, it is planned to modernize the flashlight by installing a solar panel on it on the side surface of the case, for constant recharging of the battery. After all, most of the time the flashlight is off. It will turn out such a marching, autonomous mini power plant. For mobile phone charging and lighting. On this cheerful note, let me take my leave, until we meet again on the pages of the site! Author - Tyomych (Artyom Bogatyr)

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