Hello friends and guests of the blog. The color of a cat crossing the road can tell about upcoming events, therefore experts recommend not to ignore such signs of fate.

Thanks to the observation of our ancestors and in the modern world, you can easily look into the future in order to prepare for all sorts of events and not miss your profit.

Ginger cat

By the omen, a cat of a bright red color, running in front of a walking person, promises him pleasant events in the near future. To chase away a cat - to troubles and troubles in your personal life.

Another sign says that a ginger cat is a harbinger of a festive event. For young girls, such a sign may indicate a wedding celebration or acquaintance with their future husband. Also, the sign promises the completion of difficulties and material wealth.

A red-haired cat striving to slip in front of the transport, on the contrary, promises big trouble.

Ginger cats attract love. Red cats are recommended for women who want to find a soul mate or get married.

But in order for the energy of a ginger cat to really work, it is not recommended to keep other animals of the same color in the house, as well as black pets.

It is not recommended to have ginger cats for those who have ginger hair. In general, people who want to find love will turn their luck away from themselves if they have a pet of the opposite sex and with a color similar to the color of their hair.

Gray cat

A gray cat darting in front of his feet promises the end of the difficulties associated with the financial situation.

A gray cat crossed the road - wait for great deals.

If the car hit or hit a gray cat, be in trouble. This sign indicates robbery, financial and health problems. You can cancel the effect of such a sign by adopting a kitten or donating a certain amount to animal shelters.

Gray cats will be useful to those people in whose life there are many difficulties, dangers and ill-wishers. A gray pet will divert negativity from the owner and make him unattainable for dark forces and envy.

Gray cats and cats are also an excellent talisman against damage, evil eye, love spells and other magical influences. They protect the owner from anything that can harm him.

White cat

According to legend, a white cat promises good luck, which means that if it crosses the road, the difficulties will soon end.

A white cat indicates an imminent pleasant acquaintance, which can be associated with both personal life and business partnership.

The sign says that if a white cat runs across the road, you can make a wish, and it will certainly come true.

Another sign indicates that a person is being looked after by his guardian angel.

At night, a white cat rushing across the path promises trouble. In this case, it is worth turning off the route and bypassing the dangerous place.

White cats have always been considered to be doctors. In addition to medicinal properties, they can attract helpful and kind people to their owner.

White cats have a subtle sense of everyone who enters the house, and in case of energy danger, they neutralize the negative energy of the unkind guest.

White cats with different colored eyes are considered special talismans. Their energy is very strong, they attract good luck and happy circumstances to their owners. But not everyone is recommended to start them.

Such cats will bring good only to organized and practical people. They will enhance all the positive qualities of the master's character, which will help him achieve great success in his career, love and finances.

Black cat

By omen, a cat running from right to left promises the completion of a black stripe. Also, such a sign indicates the impossibility of trickery on the part of ill-wishers.

A black cat crossing the path from left to right promises trials and minor troubles.

A black cat thrown under its feet warns of danger and that troubles await on the way. In this case, a person should choose a different path.

A cat crossing the road at an intersection indicates that soon you will have to sacrifice something for a prosperous life.

For some reason, in many countries, black cats are considered a symbol of failures and troubles, but in reality this is not so. Black cats and cats attract money to the house. They have a positive effect on business affairs.

There are signs that if you let a black cat walk its paws through important documents and agreements, the business meeting will be successful, the business will go uphill. Black cats also bring good luck to those who are engaged in trade. For such people, black cats are a real magnet for money.

Despite the fact that black cats bring good luck, some people still need to be wary of them. Those who are unlucky in life should not have a black cat, as it will attract even more problems and troubles.

And in general, those who believe in the sign of black cats should not have such a pet. But lucky people just need to get a cat of this color, then the luck will increase several times.

Multicolored cat

A motley animal running across the path indicates a lucky break. Usually, after such a sign, luck pursues a person for a whole week.

The tricolor cat promises quick replenishment for childless couples, and good news about their offspring for families with children. Unmarried, such a sign indicates a quick meeting with the second half.

A tricolor cat, according to the omen, is capable of removing evil eyes and damage, therefore, if she crossed the road, it is worth checking yourself for negativity.

The tricolor cat is considered a universal talisman. It can be started by everyone, without exception. She will attract prosperity, money, love, luck and health to the house.

Cold smoking of fish and meat products is troublesome. In the room where these products are smoked, the temperature should be maintained at no higher than 25 ° C and constant smoking for about seven days.

A technological process using an electric field is now known, which reduces this work to several hours.

The installation is a housing 1 made of galvanized iron. One side of the box is door 2, hinged. Hangers 3 are located behind it (in the vertical part of the box). They are scraps of steel (preferably stainless) wire Ø3-4 mm. Hangers are installed in insulating sleeves 4.

Each hanger is connected to a high-voltage (carefully, high voltage) wire from the scanner (BR) of the old TV. In addition to the BR, you must have a power supply from the same TV.

The negative wire (body) is connected to the box. A motor 5 with a power of 300-500 W is installed at the lower bell. A cast-iron disc 6 Ø80-100 mm and 20-30 mm thick is fixed on the motor axis. An alder block 7 is pressed against the cast-iron disc by a powerful spring.

Having hung salted dry fish (meat products) on hangers, they turn on the motor and the scanner. After a few hours (from 1.5 to 6 hours, depending on the size of the smoked products), smoking ends.

Read how in a city apartment.

Hello everybody. Today let's talk about the well-known sweet, indispensable in cooking and medicinal product Honey.

There are countless varieties of honey in the world: apple, equalipt, pumpkin, tulip, mountain ash, dandelion, carrot, mint, burdock, chestnut, cornflower. Information about the most useful varieties of honey in this article.

Lime: antibacterial, anti-inflammatory and expectorant action. It is useful in the treatment of angina, rhinitis, laryngitis, bronchitis, asthma, inflammation of the gastrointestinal tract, kidney disease, biliary diseases. Strengthens the heart.

Buckwheat: antibacterial action. Take for diseases of the respiratory tract and lungs, nervous disorders, atherosclerosis. Strong antioxidant. Prevents anemia, improves vision, memory.

Acacia: antimicrobial action. General tonic. Helps with insomnia, gastrointestinal, kidney diseases. Diluted, aqueous solutions and ointments for the treatment of eyes, eczema.

Donnikovy: antispasmodic and anti-inflammatory action. For diseases of the respiratory tract, varicose veins, insomnia, high blood pressure, neuroses, headache. For lactation in nursing mothers.

Chestnut: antimicrobial, bactericidal, antiseptic effect. Use in the treatment of respiratory diseases, tonsillitis, asthma, prostatitis, nephritis, cystitis, neuroses, insomnia. Increases appetite, stimulates liver function.

Lugovoi: antibacterial, anti-inflammatory, analgesic effect. With kidney disease. Natural immunostimulant and energy drink. Normalizes metabolism, speeds up metabolism.

Fruit: antimicrobial, dietary action. To improve blood composition, enhance immunity.

Mountain: tonic, antimicrobial and antibacterial action. In the treatment of diseases of the gastrointestinal tract, liver. dizziness, shortness of breath, atherosclerosis, insomnia. An excellent sedative.

Storage conditions:

1 ... If the conditions are met, honey is stored for 2-3 years. In a small glass jar with a capacity of 0.5 liters.

2 ... In a dark place. Ideally in a dark glass jar.

3 ... At temperatures from +5 to +10 degrees.

4 ... In places without strong odors (fish, spices).

Natural honey:

Consistency - liquid honey stretches in a thin, uniform "thread", stacked in layers. Candied honey is soft, plastic oily, does not stick to the spoon.

Smell and taste - aromatic, fragrant honey completely dissolves in the mouth, causing a slight burning sensation in the throat.

Impurities - may contain impurities such as pollen, wax particles, propolis.

The weight - one liter weighs more than 1.4 kg.

Fake:

Consistency - the trickle is intermittent, honey drips from the spoon. In candied honey, crystallization is rough, uneven, forms lumps, sticks to the spoon.

Smell and taste -smells of burnt sugar, has a candy, confectionery flavor.

Impurities - does not contain impurities.

The weight -one liter weighs less than 1.4 kg.

How to check honey:

1 ... Bring a lighted match to the honey. High-quality honey will not melt and fizzle immediately.

2 ... When diluted with water, natural honey does not form a sediment. If you add 2 drops of iodine to the solution, it does not turn blue.

3 ... Apply honey to paper. If damp spots form around, the honey is diluted.

4 ... Dip a slice of stale bread in the honey. After 8-10 minutes, the bread should remain firm and not soften.

I really hope that the information will be useful when buying and using the irreplaceable and healthy product - Honey !!!. All the best.

PILOT_SVM 15-08-2016 14:33

There is an old mobile power supply (so-called "charging").
The output is 5.25 V.
It is necessary to power the device from it, which runs on two AA batteries.

Is there an easy way to downgrade to 3V?

PILOT_SVM 15-08-2016 14:40

Postoronnim V 15-08-2016 17:39

For example a resistor. And if so, what kind of resistance?

The resistor will extinguish up to three volts only under the condition of constant current consumption.
But if the current consumption decreases, then at the output you will get a voltage higher than three volts (in the future, the same 5.25 V.). And it's good if the three-volt device can withstand it.
And the current will increase - the voltage will be below three volts (in the future, to zero).
The easiest way is to turn on a stabilizer, which, at the very least, can be replaced by connecting several diodes in series.
The voltage drop across the silicon diode is in the region of 0.6-0.8-1.0 volts.
3-4 diodes, just decrease 5.25 to three volts. Take diodes acc. maximum current consumption of a three-volt load.

Shl. Yes, I forgot to say ..
Don't do as Dachnik_Miha suggested.
That circuit is a current regulator, not a voltage regulator.
With all the ensuing consequences of increasing the voltage at the final load, as in the case of just a resistor.

unname22 16-08-2016 11:48

One drops 0.7 volts roughly.

PILOT_SVM 16-08-2016 12:08

correctly suggested diodes, only you need simple rectifiers, not Schottky.
One drops 0.7 volts roughly.

Tell Mark pzhlsta!

Postoronnim V 16-08-2016 13:44

For domestic use, strength will be sufficient.

unname22 16-08-2016 13:56

PILOT_SVM
tell me which store you will buy - we will choose from the assortment.

PILOT_SVM 19-08-2016 22:01

What is the current consumption of a three-volt load?
Well, or at least tell me what the max. is the current allowed on the charger?
In principle, you can, of course, take whatever KD202 and their current supply will definitely be enough, but, with knowledge of the max. current consumption by the load .. you can pick up smaller diodes and, without puzzling where to place them, .. take and just solder them directly into the gap of one of the supply wires .. and insulate on top.
For domestic use, strength will be sufficient.

But I will.

And it's probably easier to say what kind of consumer.
It's an electric motor.
Simplest.
In the network, he, a switch, two batteries.

And moreover - the engine is completely oak and eats up batteries (accumulators) in 15-20 minutes. Obviously, this is not the most economical consumer.
And it seems to me that such a mode for batteries is not the easiest one.
So I want to make it on mains supply.

I will measure the current consumption and report it.

PILOT_SVM 19-08-2016 22:04

quote: Originally written by unname22:
PILOT_SVM
tell me which store you will buy - we will choose from the assortment.

In St. Petersburg there are many shops with electronics and electrics.
Surely, if two or three types of diodes are named (if you stopped at this option), then in one of the St. Petersburg stores I can find the desired type.

But first I will determine the current.

I'll let you know, and then it may be easier and more accurate to find the right one.

Postoronnim V 19-08-2016 22:36

quote: Originally posted by PILOT_SVM:

The question of consumer current always strains me, because It is easy to change the volts (I threw the contacts on the outputs and FSE), then the current must be measured by breaking the network (sequentially), and this needs to be fenced off.

Well, the simplest tester has a current measurement mode. Switch on the tester in this mode in series with the motor and find out the real current consumption.
Only in this case the engine must be loaded, because in no-load mode, the current is always lower than under the working load on the motor.
If only one voltmeter is available, then connect a 1 ohm resistor in series with the motor and the voltage across this resistor will be approximately numerically equal to the current consumption.

By the way, the permissible load current is usually written on chargers for a mobile phone. Usually it is 0.5-1 A.

PILOT_SVM 19-08-2016 23:03

quote: Originally written by Postoronnim V:
1. Well, the simplest tester has a current measurement mode.

2. Switch on the tester in this mode in series with the motor and find out the real current consumption.

3. Only in this case the motor must be loaded, because in no-load mode, the current is always lower than under the working load on the motor.

4. If you have only one voltmeter, connect a 1 ohm resistor in series with the motor and the voltage across this resistor will be approximately equal to the current consumption.
Instead of a resistor, you can take a piece of thin wire with a resistance of 1 ohm. however, this also requires an ohmmeter.

5. By the way, the permissible load current is usually written on chargers for a mobile phone. Usually it is 0.5-1 A.

2. This is exactly what I plan to do. You just need to make a "insert" for this.

3. In fact, the engine is not power, but turns the impeller. So there isn't much of a difference.

4. A multitester is available.

Doesn't pull.

AZProtect 20-08-2016 01:28

quote: Originally posted by PILOT_SVM:

It is necessary to power the device from it, which runs on two AA batteries.

quote: Originally posted by PILOT_SVM:

And moreover - the engine is completely oak and eats up batteries (accumulators) in 15-20 minutes. Obviously, this is not the most economical consumer.

Let's say a battery with a capacity of 1000 mAh (or 1 Ah)
15 minutes is 1/4 hour.


If I don't confuse anything.

PILOT_SVM 20-08-2016 02:05

quote: Originally written by AZProtect:
Let's say a battery with a capacity of 1000 mAh (or 1 Ah)
15 minutes is 1/4 hour.
Total consumption is about 4 amperes maximum.
At 3 volts, this is a motor of about 12 watts.
If I don't confuse anything.

p.s. in other words, a line of ~ 8 watts of heat must be dissipated on diodes.

In these calculations, I am not strong.
Batteries for 2700 mA.

Postoronnim V 20-08-2016 06:46

quote: Originally posted by PILOT_SVM:

And the insertion of a 1 Mohm resistor into the network gave such a drop in the springs that the engine did not pull.
At first it showed - 2 V, then generally 1 V.
Doesn't pull.

5. The charging says - 4.9 V and 450 mA.

Of course, there will be a drop equal to almost all voltage
Because 1 megohm is a million times more than 1 ohm.

If 450 mA is written on the charger, then the diodes must also be looked for for a current not higher. From strength with a margin of 20%.
Because when the current is exceeded, the charger will burn, not the diodes.

On the other hand, if the motor is driven by a fan, then its current consumption can be considered constant and a simple resistor is enough.
But in order to calculate the resistance and power dissipation of this resistor, you still need to find out the current consumption of the motor.

quote: Originally posted by PILOT_SVM:

In these calculations, I am not strong.
Batteries for 2700 mA.

But in the process of work, obviously - for about 15 minutes the motor hums strongly, and then it sags noticeably.

And as far as I remember - for nickel-metal hydrite batteries, a quick discharge is undesirable.

Judging by what you are telling, a 450mA charger simply won't work.
Measure the current consumption from the batteries.
An ordinary multitester has a separate socket for measuring ampere currents (10A)
Leave one probe in the "ground" socket, put the second in the 10A socket, select the 10A mode with the switch and connect the probes to the motor power circuit in series.
In this case, it would be nice to use a second tester to monitor the voltage on the batteries, since if the batteries are half-alive, then this voltage can sink, and we need to know its value to calculate the resistor or diode.

RTDS 20-08-2016 08:46

They have already piled up schemes ...
To start, turn on the motor directly to the charger, to 5 volts.
It is likely that the voltage will subside to the required voltage - 3.4-4.5 volts will not overload your motor, especially since it also turns the impeller ...

unname22 20-08-2016 14:03

Just go to the store and say you need a 5 Ampere diode with a voltage of 50 volts to infinity, just not Schottky, they will pick it up easily.

hunter1957 21-08-2016 22:08

quote: The question of consumer current always bothers me, because It is easy to change the volts (I threw the contacts on the outputs and the FSE), then the current must be measured by breaking the network (sequentially), and this needs to be fenced off. But I will. And it’s probably easier to say what kind of consumer. This is an electric motor. The most simple. he network, a switch, two batteries. And moreover - the engine is completely oak and eats batteries (accumulators) in 15-20 minutes. Obviously, this is not the most economical consumer. And it seems to me that such a mode for batteries is not the easiest. So I want to make it on the mains supply. I will measure the current consumption and report it.

quote: I'm not strong in these calculations. The batteries are at 2700 mA. But in the process of operation it is obvious - for about 15 minutes the motor hums strongly, and then it sags noticeably. And as far as I remember, a fast discharge is undesirable for nickel-metal hydrite batteries.

From the initial data, it appears: Power source two metal hydride batteries with a nominal capacity of 2.7A / H; voltage of fully charged batteries 2.4 volts; final voltage for them is 1 volt per 1 cell. In a quarter of an hour, the batteries sit down .... The real discharge current is about 10 amperes, when choosing power supply, you must also take into account that the starting short-term current consumption will be about 2-3 times more ... Your 5 volt charging is unsuitable - it does not give out the required current ...
Of the available mass power sources, a switching power supply unit of a computer of the ATX standard is suitable practically without alteration - there is an output of 3.3 volts 10 amperes.

alexaa1 22-08-2016 06:01

Something suggests that this is something like shearing off the pellets, there are no large amperes, a maximum of one ampere.

PILOT_SVM 22-08-2016 09:35

Measurement showed:

PILOT_SVM 22-08-2016 09:36

quote: Originally written by alexaa1:
Something suggests that this is something like shearing the pellets

Yes exactly.

hunter1957 22-08-2016 10:10

quote: Measurement showed:
Current measurement scale - 200 microAmps, 2000 microAmps, 20 milliAmps, 200 milliAmps.
The next value is 10 A, and the contact must be rearranged.
On the scale of the multitester, 200 mA (max) was set - at the same time, at first (without load), 3-4.5 jumped out on the display, then smoothly slid down to 1-1.2.
With a small load, it began to jump 2, 3 and up to 4.8.
True, sometimes it dropped even more, but for a short time.
On the motor there are no markings, except for "-" and "+" and an arrow (if we assume that this is the direction of rotation with just such a connection of plus and minus.
And - I looked at the direction of movement - for some reason the contacts are confused.
What would it mean - I am in confusion.

You have determined the prices for oats .... Apparently, your batteries have lost their capacity. For the correct current, you need to measure at the limit of 10 amperes and use high-quality alkaline batteries ... In reality, the starting current is short-term for such motors 5-10 amperes, the working current is more 3 amperes .... Go to the computer engineers - set the task to connect the motor to 3.3 volts and you will be happy. The wire for connecting to the motor is at least 0.75 mm2.

PILOT_SVM 22-08-2016 11:47

quote: For the correct current, you need to measure at the limit of 10 amperes and use high-quality alkaline batteries

At 10 A, it does not show at all and does not work.
New batteries - 2700 mA.
So your numbers are clearly overstated.

hunter1957 22-08-2016 12:09

quote: At 10 A - it does not show and does not work at all. The batteries are new - 2700 mA. So your numbers are clearly overstated.

How do you charge the batteries? I have the correct charge from Lacrosse - it allows you to measure with great accuracy the real capacity of the battery, train and recover ... A new fresh battery may have a real capacity of 0.5A / h. You have a faulty device or you simply do not know how to do it. For batteries AA / AAA, the voltage is 1.5 volts, the operating and internal resistance is less than that of the battery. With electronics for half a century ... Current measurement is performed only when connected in series ... Try if your device works correctly on measuring resistance, measure resistance motor with several rotor positions ....

PILOT_SVM 22-08-2016 13:14

quote: How do you charge the batteries? I have the correct charge from Lacrosse

Charging GP, and the same brand of battery.

quote: AA / AAA batteries have a 1.5 volt operating and internal resistance less than a battery

Batteries have 1.5 V, while batteries have 1.3 V.

When measuring the tension and current strength, the tester did not show, and when measuring the resistance, it showed a weak battery.
Buy a battery - I will repeat the resistance measurements.

hunter1957 22-08-2016 13:40

quote: Charging GP, and the same brand of battery.

Charging is by and large the simplest budget, it kills the batteries pretty quickly ... IMHO GP batteries I have never come across decent ...

PILOT_SVM 22-08-2016 16:13

Charging is by and large the simplest budget, it kills the batteries pretty quickly ... IMHO GP batteries I have never come across decent ...

And what does "kill quickly" mean?

The charge says:
for AA batteries:
If there are 4 pieces on the charge, then at a voltage of 2.8 V, 525 mA is given.
If there are 2 pieces on charging, then at 2.8 V, 1050 mA each.

What is wrong?

Wrong mA?
Need more? Need less?

Need a variable charging mode?

The previous set of batteries (2500 mA) worked for 4 years.
Few?

Do your batteries last 10 years?

hunter1957 22-08-2016 17:05

quote: On the charging it is written: for AA batteries: If there are 4 pieces on charging, then at a voltage of 2.8 V it is given at 525 mA. If there are 2 pieces on charging, then at 2.8 V, at 1050 mA. What is wrong? Ma? Need more? Need less? Need variable charging? The previous set of batteries (2500 mA) worked for 4 years. Not enough? Your batteries last 10 years?

In the last century, my son's player was powered by GP batteries - a little over a year was enough .... According to all manuals, the standard charge mode is 0.1 from full capacity for 14 hours, discharge with a current of no more than 0.1 capacity for 10 hours or up to a voltage of 1 volt. The declared resource is 500 charge-discharge cycles .... Thanks to Lacrosse, the Soviet TsNK-0.45 finger batteries are still working, according to estimates, they have already worked for 800 cycles .... GPs immediately began to lose capacity and after 50 charge-discharge cycles they had a proprietary charge. less than 15% of the declared capacity .... The computer power supply is guaranteed without alterations to ensure 100% performance of your gadget ....

PILOT_SVM 22-08-2016 18:49

quote: According to all manuals, the standard charge mode is 0.1 from full capacity for 14 hours

Usually, they write on the batteries themselves - 0.1 of the capacity for 16 hours.

quote: The declared resource is 500 charge-discharge cycles .... Thanks to Lacrosse, the Soviet TsNK-0.45 finger batteries are still working, according to estimates, 800 cycles have already worked

As I said, the GP 2500 mA batteries served for 4 years. It is especially stressful in the summer. I think no less than 500 cycles.
By the way - earlier for Nickel-metahydr batteries, everyone declared 1000 cycles.
Now, for some reason, 500.

By the way, about the brands - I really hoped for VARTA batteries,
but they served no more than a GP.

By the way - you said that you need a power supply unit and 0.75 mm2 wires.
And in fact there are wiring like a thread?

But in general, everything is clear about the batteries.
They work for me and everything is fine with that.

I would like to deal with the power supply of the motor.
And here, the parameters you declared seem excessive to me.

hunter1957 22-08-2016 20:02

quote: Speaking of brands, I really hoped for VARTA batteries, but they did not last more than GP. By the way, you said that you need a power supply unit and 0.75 mm2 wires. And in fact the wiring there is about like a thread? 20. But in general About the batteries everything is clear. They work for me and everything is fine with this. I would like to deal with the power supply of the motor. And here, the parameters you declared, seem to me excessive.

Both Warta and GP and many more brands are produced in China, not only of different quality and different purposes and different selling prices ... Our hucksters try to take the most budgetary ones, for Western Europe and the USA their hucksters buy more expensive and high quality ones. power - the margin is not superfluous - just 10 amperes maximum current in the specification. The wire according to the specification, if I am not mistaken, should be? 18 or? 20 - good brands in premium power supplies may have a thicker wire ...

PILOT_SVM 28-08-2016 19:54

can you connect a 1.5 V light bulb in series?

hunter1957 29-08-2016 12:15

quote: can you connect a 1.5 V light bulb in series?

It makes no sense - the resistance of 1.5 V lamps is too high ...
There is no alternative to a computer power supply unit for you, a universal laboratory power supply unit costs at least an order of magnitude more ... reverse polarity diode circuit simply will not work. The voltage drop across the diode is 0.7-1.5 volts depending on the current and the letter in the marking.

PILOT_SVM 17-09-2016 20:25

One more question about charging.
Disassembled the broken charger.
The reason is most likely in the burnt out transistor, a piece of the case flew off from it.
And along the way I saw that 4 diodes were drawn on the board, which most likely should make up a diode bridge, but ...

There is only one diode, but three are simply not there.
Moreover, the diode is not located after the transformer, but immediately after the contact at 220 V.
Diode size - length 6-7 mm, diameter -2-2.5 mm.

Are there really such Lilliputian parts at 220 V?

I have diodes designed for 220 - they are very large and the contacts are there for nuts.

hunter1957 17-09-2016 20:35

quote: Another question on charging. I disassembled the broken charger. The reason is most likely in a burnt out transistor, a piece of the case flew off from it. And along the way I saw that 4 diodes were drawn on the board, which most likely should make up a diode bridge, but ... one diode, but three simply do not. Moreover, the diode is not located after the transformer, but immediately after the contact at 220 V. The diode is 6-7 mm long, dia. -2-2.5 mm. Are such Lilliputian parts really at 220 V? I have diodes designed for 220 - they are very large and the contacts are there for nuts.

Switching power supply.
Size does not depend on voltage, size depends on rectified current and power dissipation.

PILOT_SVM 18-09-2016 13:25

quote: Originally written by hunter1957:
Switching power supply.
Size does not depend on voltage, size depends on rectified current and power dissipation.

I have a feeling that you are a person in the subject.
But it is difficult to understand you.
Probably this is inherent in all specialists.

hunter1957 19-09-2016 01:04

quote: I have a feeling that you are a person in the subject. But it is difficult to understand you. Probably this is inherent in all specialists.

If there is a desire to delve into there is a wonderful two-volume / three-volume Horowitz and Hill "The Art of Circuitry" where it is very clearly explained what works. There is a chapter devoted to power supplies - the volume of the chapter is small and practical diagrams and their calculation are given ...

PILOT_SVM 19-09-2016 09:32

quote: Originally written by hunter1957:
If there is a desire to delve into there is a wonderful two-volume / three-volume Horowitz and Hill "The Art of Circuitry" where it is very clearly explained what works. There is a chapter devoted to power supplies - the volume of the chapter is small and practical schemes and their calculation are given ...

At the moment - I'm 6 something easier, like "press the button, get the result."
Like the advice voiced earlier - put a diode.

hunter1957 20-09-2016 02:15

quote: At the moment, it's easier for me, like "press the button, get the result." Like the advice that was sounded earlier - put a diode.

Everything is not so simple in your case - the diodes are different, for different voltages and currents and with different voltage drops at different currents ... Read the book, at least for general development and understanding of the processes, the book is written in simple accessible language ...

Postoronnim V 20-09-2016 08:54

Although I have already explained several times above, I will repeat:
In this case, it is imperative to know the maximum current consumption of the powered device. (further I consumption max.)

Next, we are looking for diodes designed to operate at this current.
This parameter of the diode is called I pr. Max. (There is also I pr. Max. Impulse - but in this case you do not need to focus on it).
Here you choose diodes with I pr. Max. not less than one and a half I cons. Max.
Next, we look at such a diode parameter as the forward voltage on an open diode - U pr.
This parameter is different for different types of diodes. From small fractions of a volt (Schottky diodes, germanium diodes) to several volts (thyristors, LEDs, stabilizers).
In this case, the most ordinary silicon rectifier diodes are enough.
For conventional silicon rectifier diodes U pr. In the region of 0.5-1.0 volts. (and the spread of 0.1-0.3 volts can be even on diodes of the same type .. and on different direct currents).
Here, be guided by the passport U pr .. buy 2-3 more diodes, connect them in series, connect the load, control the voltage with a voltmeter. if it is slightly less than required, exclude (short-circuit) one diode. The voltage across the load will increase by the amount of drop U pr. On a specifically disconnected diode.
It will not be enough - exclude the next diode.
Etc. until the desired result is achieved.

Shl. Of the most important parameters of the diode, there is also the maximum allowable reverse voltage, but in this case it can be ignored, because Almost any rectifier diode will withstand 5-10 volts of reverse, and then their reverse-permissible will also add up.

PILOT_SVM 20-09-2016 11:29

PILOT_SVM 20-09-2016 17:16

If possible - tell me, can you make an addition to reduce the voltage from these parts?

hunter1957 20-09-2016 18:34

quote: If possible, tell me, can you make an addition to reduce the voltage from these parts?

Six elements are located at 3 o'clock with a very high probability of diodes, it will take one minute to check the serviceability with a multimeter.
I can't reliably determine the brand from the photo - I'm not a magician .... Wangyu that even if these diodes are in good working order, they with a very high degree of probability will not be able to work due to exceeding the permissible maximum current ..........

PILOT_SVM 21-09-2016 20:55

There are diodes: 5 pcs. IN4007.
1 pc - DB 3 bufan

hunter1957 21-09-2016 21:25

quote: There are diodes: 5 pcs. IN4007.1 pcs - DB 3 bufan

These parts are not suitable, I justify: IN4007 has a maximum current of 1 ampere - if it is exceeded, it will simply fail - the starting current of your toy is much more than 1 ampere ...... DB 3 - there is no diode - it is a dinistor and it is, by definition not suitable ...

PILOT_SVM 21-09-2016 22:33

Can you fix something with resistors?

hunter1957 22-09-2016 08:55

quote: Can you fix something with resistors?

These are not ... Here, resistors are needed with much higher power dissipation and resistance less than 1 ohm - they are very rare, have large dimensions and sometimes cost a lot of money.

There is another way to reduce the voltage across the load, but only for DC circuits. See about here.

Instead of an additional resistor, a chain of diodes connected in series, in the forward direction, is used.

The whole point is that when a current flows through a diode, a "forward voltage" falls on it, equal, depending on the type of diode, power and current flowing through it - from 0.5 to 1.2 Volts.

On the germanium diode, the voltage drops from 0.5 to 0.7 V, on the silicon diode from 0.6 to 1.2 Volts. Based on how many volts you need to lower the voltage across the load, turn on the corresponding number of diodes.

To lower the voltage by 6 V, approximately turn on: 6 V: 1.0 \u003d 6 pieces of silicon diodes, 6 V: 0.6 \u003d 10 pieces of germanium diodes. The most popular and available are silicon diodes.

The above circuit with diodes is more cumbersome in execution than with a simple resistor. But, the output voltage, in a circuit with diodes, is more stable and less dependent on the load. What is the difference between these two ways to lower the output voltage?

In Fig 1 - additional resistance - resistor (wire resistance), Fig 2 - additional resistance - diode.

A resistor (wire resistance) has a linear relationship between the current passing through it and the voltage drop across it. How many times the current increases, the voltage drop across the resistor will also increase by the same amount.

From example 1: if we connect another one in parallel to a light bulb, then the current in the circuit will increase, taking into account the total resistance of the two light bulbs to 0.66 A. The voltage drop across the additional resistor will be: 12 Ohm * 0.66 A \u003d 7.92 V The lights will remain: 12 V - 7.92 V \u003d 4.08 V. They will burn in the floor.

A completely different picture will be if instead of a resistor there is a chain of diodes.

The relationship between the current flowing through the diode and the voltage dropped across it is nonlinear. The current can increase several times, the voltage drop across the diode will increase by only a few tenths of a volt.

Those. the greater the diode current, the less (compared to a resistor) its resistance increases. The voltage drop across the diodes depends little on the current in the circuit.

Diodes in such a circuit act as a voltage stabilizer. Diodes must be selected according to the maximum current in the circuit. The maximum permissible diode current must be greater than the current in the calculated circuit.

The voltage drops across some diodes at a current of 0.5 A are given in the table.

In AC circuits, a capacitor, inductance, dynistor or thyristor (with the addition of a control circuit) can be used as an additional resistance.

According to the PUE, a voltage of no higher than 50 Volts should be used to power portable lighting, and when working in especially dangerous and confined spaces - 12 Volts (PUE 6.1.16-18). In this case, the power supply must be carried out through transformers. This is to prevent electric shock. And the output parameters of power supplies or batteries do not always allow connecting gadgets or other electronics. In this regard, we will tell you how to lower the DC and AC voltage to the value you need.

Lowering the AC voltage

Let's consider typical situations when you need to lower the voltage in order to connect a device that operates on AC, but its supply voltage does not correspond to the usual 220 Volts. It can be both various household appliances, tools, and the lamps mentioned above.

Connecting household appliances from the USA for 110 V to a 220 V network

Perhaps the most common situation arises when a person buys some kind of device from foreign online stores, and upon receiving it, determines that it is designed for power supply from 110 volts. The first option is to rewind the transformer supplying the device, but most devices operate from a switching power source, and to connect a power tool, it is better to do without rewinding at all. To do this, you need to use a step-down transformer. In addition, you can lower the voltage in the network using an autotransformer or a conventional transformer with 110-127V taps from the primary winding - these were often found in Soviet TVs and other electrical appliances.

However, when using such a transformer connection, if a part of the winding breaks after tapping 110 Volts (see the figure below), all 220V will fit the device, and it will fail.

If we talk about ready-made devices, then we can pay attention to the “SHTIL” autotransformers.

Important! When buying transformers or autotransformers, consider the rated current of its windings and the power that it will withstand.

A more reliable solution to the problem would be to lower the voltage from 220 to 110V or from 220 to 127V using a transformer. There are many companies on the market that sell such products, mostly toroidal transformers. They come in metal boxes or smaller cases with a built-in socket, as well as adapters in plastic cases.

Let's summarize by listing the main requirements for a transformer for powering 110V devices:

1. The output of the transformer should be 110V, and the input should be 220V.
2. The power of the transformer must be at least 20% higher than the power of the connected device.
3. It is advisable to protect the primary and secondary circuits with a fuse.
4. Access to high voltage terminals should be limited and all connections insulated.

Lowering the voltage to power low-voltage lamps

At the beginning of the article, we mentioned that the portable lamp should be powered from reduced voltage. In everyday life, this issue will be especially relevant for motorists when repairing a car in the garage. The same lamps are also used as a local light source on machine tools (drilling, turning, sharpening and others).

In order to lower the voltage from 220 to 36V, you can use transformers of the brand:

• OSO 0.25 220 / 36V;
• OSM 0.063kW 220/36;
• OSZR 0.063kW 220 / 36V;
• Box with a step-down transformer YATP-0.25 220 36V (this is a ready-made solution in a metal case for indoor installation, protection class IP54).

To reduce the voltage from 220 to 12V, you can use transformers of the brand:

• OSO25 220 / 12V;
• TRS 300W AC 220 V-AC 12V (toroidal does not take up much space);
• 30VA, 230 / 12V, 2.5A INDEL TSZS30 / 005M (low power for mounting on DIN rail).

Reducing voltage in the house

Along with, there is often a problem with overvoltage and undervoltage. This leads to premature failure of heating devices, lamps and other devices at the consumer. Let's say you need to lower the voltage from 260 to 220V, then your choice is to use a voltage stabilizer. They are of different types, the cheapest of them is a relay one, in fact it is an autotransformer in which the relays automatically switch the taps from the winding.

If you need to protect a specific device, for example, a computer, use low-power models with a capacity of about 1000 VA (1 kVA), such as SVEN VR-L1000, its cost is 17-20 dollars. But keep in mind that their active output power is less than the indicated total in Volt-Ampere. For example, a 1 kVA model can supply loads up to 0.3-0.4 kW. Also look at the characteristics. The specified model can withstand up to 285 volts, but most models rest against 260 V.

To protect the whole house, in most cases, the RUCELF SRWII-12000-L model will suffice, its total power is 12000 VA, and the active power load capacity is 10000 W. It can handle input voltages up to 270V.

To learn more about how to choose a voltage stabilizer and what kind of stabilizers there are, we told in the articles:

Ballast capacitor for supplying low-power devices

To power low-power devices, you can do without a transformer - one capacitor. Such a circuit is called a transfluoridable power supply unit on a ballast capacitor. Its principle of operation is based on limiting the current using the reactance of the capacitor. Below you can see the options for its implementation.

The calculation of the capacity of the ballast capacitor for transformerless power supply is based on the current consumption of the load and its supply voltage.

Or according to this formula, they give approximately the same result:

By the way, the expression under the root as a result, when calculating capacitors for powering devices from 5-20V, gives about 220, or a value equal to Uinput.

Such a power source is suitable for connecting receivers, LEDs, night lights, charging small batteries and other low-power consumers.

Lowering the DC voltage

When designing electronics, it is often necessary to lower the voltage of an existing power supply. We will also look at a few typical situations.

If you work with microcontrollers, you may have noticed that some of them operate from 3 volts. Finding the right power supply can be tricky, so you can use a phone charger. Then you need to lower its output from 5 to 3 volts (3.3V). This can be done by lowering the output voltage of the power supply by replacing the zener diode in the feedback circuit. You can achieve any voltage, both high and low, by setting the Zener diode of the desired rating. It can be determined by the selection method, in the diagram below it is highlighted with a red ellipse.

And on the board, it looks like this:

On chargers of a more advanced design, an adjustable zener diode TL431 is used, then adjustment is possible by replacing the resistor or the ratio of a pair of resistors, depending on the circuitry. They are marked in red in the diagram below.

In addition to replacing the zener diode on the memory board, you can lower the voltage using a resistor and a zener diode - this is called a parametric stabilizer.

Another option is to install a chain of diodes in the open circuit. Each silicon diode will drop about 0.6-0.7 volts. So you can lower the voltage to the desired level by dialing the required number of diodes.

It is often necessary to connect the device to the vehicle's on-board network, it ranges from 12 to 14.3-14.7 Volts. To lower the DC voltage from 12 to 9 volts, you can use a linear regulator type L7809, and to lower it from 12 to 5 volts, use the L7805. Or their analogues ams1117-5.0 or ams1117-9.0 or amsr-7805-nz and the like for any desired voltage. The connection diagram of such stabilizers is shown below.

To supply more powerful consumers, it is convenient to use pulse converters to lower and adjust the voltage from the power source. An example of such devices are boards based on LM2596, and in English-language online stores they can be found by searching for "DC-DC step down" or "DC-DC buck converter".

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