Using Schottky diodes in a charger. Electrical diagrams for free. What diodes are used for the charger. For the "Telephone line holding device" circuit

We are considering a car battery charger made on the basis of a converter for powering 12V halogen lamps of the TASCHIBRA type. Converters of this type are often found on sale among electrical products. TASCHIBR is distinguished by fairly good reliability and preservation of performance at negative ambient temperatures.

This device is made on the basis of a self-oscillating converter with a conversion frequency of approximately 7 to 70 kHz, which depends on the resistance of the converter connected to the output active load. As the load power increases, the conversion frequency increases. Interesting feature TASCHIBR is a disruption of generation when the load increases beyond the permissible limit, which can be a kind of protection against short circuit. Let me make a reservation right away that I was not going to consider options for the so-called “rework” or “refinement” of these converters, which is described in some publications. I propose to use TASCHIBR "as is" with the exception, perhaps, of increasing the number of turns of the secondary winding, which is necessary in order to ensure the charging current of the desired value

As is known, to ensure the required charging current, a voltage of at least 15-16 V must be generated on the secondary winding.

The picture shows that the existing white secondary winding wire was used as additional turns. For a 50 W converter it was enough to add 2 turns to the secondary winding. In this case, it is necessary to ensure that the direction of winding is carried out in the direction (i.e., consistent) of the existing winding, in other words, that the magnetic flux of the newly appearing turns coincides in direction with the magnetic flux of the “native” secondary winding of TASHIBR, designed to power 12V halogen lamps and located on top of the primary at 220V.

The bridge rectifier is made from Schottky diodes such as 1N5822. It is possible to use domestic high-speed diodes, for example KD213.

The optimal charging process is based on limiting both the charging current and the voltage level at the battery terminals. Let's set a current of approximately 1.5 A and a voltage of no more than 14.5V. The control circuit shown in Fig. 1 has the characteristics under consideration. The key element of the circuit is a triac V type BT134-600, switched on by an optosimistor MOS3083. The current limitation is formed by the voltage drop across resistor R2 with a resistance of 1 Ohm and a dissipation power of 2 W. When the voltage drop across it exceeds 1-1.5 V, transistor VT2 opens and bypasses the LED of the optosimistor VD5, interrupting the power supply to the TASCHIBR. If it is necessary to increase the charging current level, for example to 3 - 4 A, it is necessary to reduce the resistance of resistor R2 accordingly, paying attention to the choice of the required dissipation power for this resistor. As the battery charges, the voltage at its terminals approaches 14.5V. Current begins to flow through the zener diode VD3, which causes transistor VT3 to open. At the same time, the VD4 LED begins to flicker, signaling the end of the charging process, and a current begins to flow through the VD2 diode, opening the VT2 transistor, which leads to the locking of the triac V. To indicate the fact of the opening of the triac, a transistor switch VT1 with a VD1 LED in the circuit of its collector is used . This transistor must be germanium, due to the small voltage drop across the optosimistor LED (about 1V).

Among the shortcomings charger of this type It should be noted that its performance depends on the voltage level on the battery, since, obviously, the circuit initially receives power from the battery, which should not fall below 6V to ensure the circuit is operational. However, due to the rarity similar cases- you can put up with this. If forced charging is necessary, you can install an additional SW button, as shown in the diagram, by pressing which you can bring the battery voltage to the required level.

The charger was made in a single copy. No printed circuit board was developed. The device is mounted in a machine housing of a suitable size.

List of radioelements

Designation	Type	Denomination	Quantity	Note	My notepad
VT1	Bipolar transistor	MP37B	1		To notepad
VT2	Bipolar transistor	BC547C	1		To notepad
VT3	Bipolar transistor	BC557B	1		To notepad
V	Triac	BT134-600	1		To notepad
VD1	Light-emitting diode	ARL-3214UGC	1		To notepad
VD2	Rectifier diode	1N4148	1		To notepad
VD3	Zener diode	D814D	1		To notepad
VD4	Light-emitting diode	ARL-3214URC	1		To notepad
VD5	Optosimistor	MOC3083	1		To notepad
D1	Schottky diode	1N5822	4	Diode bridge	To notepad
C1	Electrolytic capacitor	470 µF	1		To notepad
C2	Capacitor	1 µF	1		To notepad
F1	Fuse	1A	1		To notepad
R1, R3	Resistor	820 Ohm	2		To notepad
R2	Resistor	1 ohm	1	2W	To notepad
R4, R5	Resistor	6.8 kOhm	2

A fairly popular situation among motorists is the complete discharge of the battery, especially in the winter season and, as usual, there is no charger at hand. What to do if you find yourself in such a situation? In this article, you will get the most popular ways to charge batteries without breaking the bank.

A diode and a regular lamp will help. One of the most simple ways recharge the battery, and most importantly, it is very cheap, because to work you only need two elements - a simple incandescent lamp and a diode.

The diode cuts off one half-wave, thanks to which it works as a rectifier, but the only negative is that this is the second half-wave, that is, the current will still pulsate, but the battery will be able to charge. The correct question would be what level of current you will get at the output, because the charging current determines how long the battery will last you. It's simple, the current depends on the light bulb, which you can take within 40-100 watts and everything will be fine.

The lamp plays the role of an absorber of excess current and voltage, the diode acts as a rectifier, and since it is connected to an industrial network, it must be quite powerful, otherwise a breakdown will occur. The current is 10 Amps, but the rated voltage of the diode should be 400 Volts.

During operation, the diode generates a large amount of heat, which means it needs to be cooled; the easiest option is to install it on an aluminum plate or a radiator from old electronics.

The figure shows the simplest option with one diode, but in this case the current strength will drop by at least half, which means that the battery will be charged in a more gentle mode, but also longer. If you use a 150 Watt lamp as an extinguishing lamp, then full charge will happen in 6-12 hours. If there is very little time, then the current can be increased quite simply by replacing the light bulb with more powerful equipment, such as heaters or even electric stoves.

Boiler for charging.

This option works on a similar principle, but there is an additional plus: the output after rectification will be clean D.C. without any ripple thanks to the diode bridge, which smoothes both half-waves.

An ordinary boiler acts as a quenching load, but it can be replaced with other options, even with the same lamp from the first option. A diode bridge can be bought ready-made or pulled from old electrical appliances, but its voltage must be at least 400 Volts and its current strength must be at least 5 Amperes.

A diode bridge is also installed on the heat sink for better cooling, because it will get very hot. If there is no ready-made option, then the bridge can be assembled from 4 diodes, but their voltage and current must be equal and no less than in the bridge itself.

But to be on the safe side, you can bet much more more powerful elements. Schottky is ready-made assemblies from diodes, but them reverse voltage very small, about 60 Volts, which means they will burn out instantly.

Third, but an equally popular option is capacitor. The main advantage of this option is a capacitor that will dampen ripples. This charger is safer than previous versions. The charge current is set using the capacitance of the capacitor based on the formula:

I=2*pi*f*C*U

U– mains voltage, at the rectifier input is approximately 210-236 Volts. f – mains frequency, but it is a constant and equal to 50 Hz.
C– Capacitive volume of the capacitor itself.
pi– Pi number equal to 3.14.

To charge car battery within an hour you will have to assemble large capacitive modules, but this option is complex and very bad for the battery, so it will be enough to use capacitors of about 20 uF. The capacitor must be film type and the operating voltage must be 250 volts or more.

Very often there is a problem with charging a car battery, and there is no charger at hand, what to do in this case. Today I decided to publish this article, where I intend to explain all the known methods of charging a car battery, it’s interesting, really. Go!

METHOD ONE - LAMP AND DIODE

Photo 13 This is one of the simplest charging methods, since the “charger” in theory consists of two components - an ordinary incandescent lamp and a rectifying diode. The main disadvantage of this charging is that the diode cuts off only the lower half-cycle, therefore, we do not have a completely constant current at the output of the device, but you can charge a car battery with this current!

The light bulb is the most ordinary one, you can take a 40/60/100 watt lamp, the more powerful the lamp, the greater the output current, in theory the lamp is here only for current extinguishing.

The diode, as I already said, to rectify alternating voltage, it must be powerful, and it must be designed for a reverse voltage of at least 400 Volts! The diode current must be more than 10A! This is a mandatory condition, I highly recommend installing the diode on the heat sink; you may have to cool it additionally.

And in the figure there is an option with one diode, although in this case the current will be 2 times less, therefore the charging time will increase (with a 150 Watt bulb, it is enough to charge a dead battery for 5-10 hours to start the car even in cold weather)

To increase the charge current, you can replace the incandescent lamp with another, more powerful load - a heater, boiler, etc.

METHOD TWO - BOILER

This method works on the same principle as the first, except that the output of this charger is completely constant.

The main load is the boiler; if desired, it can be replaced with a lamp, as in the first option.

You can take a ready-made diode bridge, which can be found in computer units nutrition. It is MANDATORY to use a diode bridge with a reverse voltage of at least 400 Volts with a current of AT LEAST 5 Amps, install the finished bridge on a heat sink, since it will overheat quite strongly.

The bridge can also be assembled from 4 powerful rectifier diodes, and the voltage and current of the diodes should be the same as when using the bridge. In general, try to use a powerful rectifier, as powerful as possible; extra power never hurts.

DO NOT USE powerful SCHOTTTKY diode assemblies from computer power supplies, they are very powerful, but the reverse voltage of these diodes is about 50-60 Volts, so they will burn out.

METHOD THREE - CONDENSER

I like this method the most; the use of a quenching capacitor makes the charging process safer, and the charge current is determined from the capacitor’s capacitance. The charge current can be easily determined by the formula

I = 2 * pi * f * C * U,

where U is the network voltage (Volts), C is the capacity of the quenching capacitor (μF), f is the frequency alternating current(Hz)

To charge a car battery, you need to have a fairly large current (a tenth of the battery capacity, for example - for a 60 A battery, the charging current should be 6A), but to obtain such a current we need a whole battery of capacitors, so we will limit ourselves to a current of 1.3-1, 4A, for this, the capacitance of the capacitor should be around 20 µF.
A film capacitor is required, with a minimum operating voltage of at least 250 Volts, great option MBGO type capacitors of domestic production.

DIY 12V battery charger

I made this charger to charge car batteries, output voltage 14.5 volts, maximum charge current 6 A. But it can also charge other batteries, such as lithium-ion ones, since the output voltage and output current can be adjusted within a wide range. The main components of the charger were purchased on the AliExpress website.

These are the components:

Diode bridge KBPC5010.

You will also need an electrolytic capacitor 2200 uF at 50 V, a transformer for the TS-180-2 charger (see this article for how to solder the TS-180-2 transformer), wires, a power plug, fuses, a radiator for the diode bridge, crocodiles. You can use another transformer with a power of at least 150 W (for a charging current of 6 A), the secondary winding must be designed for a current of 10 A and produce a voltage of 15 - 20 volts. The diode bridge can be assembled from individual diodes designed for a current of at least 10A, for example D242A.

The wires in the charger should be thick and short. The diode bridge must be mounted on a large radiator. It is necessary to increase the radiators of the DC-DC converter, or use a fan for cooling.

Circuit diagram of a charger for a car battery

Charger assembly

Connect a cord with a power plug and a fuse to the primary winding of the TS-180-2 transformer, install the diode bridge on the radiator, connect the diode bridge and the secondary winding of the transformer. Solder the capacitor to the positive and negative terminals of the diode bridge.

Connect the transformer to a 220 volt network and measure the voltages with a multimeter. I got the following results:

The alternating voltage at the terminals of the secondary winding is 14.3 volts (mains voltage 228 volts).
The constant voltage after the diode bridge and capacitor is 18.4 volts (no load).

Using the diagram as a guide, connect a step-down converter and a voltammeter to the DC-DC diode bridge.

Setting the output voltage and charging current

There are two trimming resistors installed on the DC-DC converter board, one allows you to set the maximum output voltage, the other allows you to set the maximum charging current.

Plug in the charger (nothing is connected to the output wires), the indicator will show the voltage at the device output and the current is zero. Use the voltage potentiometer to set the output to 5 volts. Close the output wires together, use the current potentiometer to set the short circuit current to 6 A. Then eliminate the short circuit by disconnecting the output wires and use the voltage potentiometer to set the output to 14.5 volts.

Reverse polarity protection

This charger is not afraid of a short circuit at the output, but if the polarity is reversed, it may fail. To protect against polarity reversal, a powerful Schottky diode can be installed in the gap in the positive wire going to the battery. Such diodes have a low voltage drop when connected directly. With such protection, if the polarity is reversed when connecting the battery, no current will flow. True, this diode will need to be installed on a radiator, since a large current will flow through it during charging.

Suitable diode assemblies are used in computer power supplies. This assembly contains two Schottky diodes with a common cathode; they will need to be paralleled. For our charger, diodes with a current of at least 15 A are suitable.

It must be taken into account that in such assemblies the cathode is connected to the housing, so these diodes must be installed on the radiator through an insulating gasket.

It is necessary to adjust the upper voltage limit again, taking into account the voltage drop across the protection diodes. To do this, use the voltage potentiometer on the DC-DC converter board to set 14.5 volts measured with a multimeter directly at the output terminals of the charger.

How to charge the battery

Wipe the battery with a cloth soaked in soda solution, then dry. Remove the plugs and check the electrolyte level; if necessary, add distilled water. The plugs must be turned out during charging. No debris or dirt should get inside the battery. The room in which the battery is charged must be well ventilated.

Connect the battery to the charger and plug in the device. During charging, the voltage will gradually increase to 14.5 volts, the current will decrease over time. The battery can be conditionally considered charged when the charging current drops to 0.6 - 0.7 A.

Car charger

Attention! The circuit of this memory is intended for fast charging your battery in critical cases when you urgently need to go somewhere in 2-3 hours. Do not use it for everyday use, as the charge is constant voltage, which is not the best charging mode for your battery. When overcharging, the electrolyte begins to “boil” and toxic fumes begin to be released into the surrounding space.

Once upon a time in the cold winter time

I left the house, it was bitterly cold!

I get into the car and insert the key

The car is not moving

After all, Akum died!

A familiar situation, isn't it? 😉 I think all car enthusiasts have found themselves in such an unpleasant situation. There are two options: start the car from the charged battery of the neighbor’s car (if the neighbor doesn’t mind), in the jargon of car enthusiasts this sounds like “lighting a cigarette.” Well, the second way out is to charge the battery. Chargers are not very cheap. Their price starts from 1000 rubles. If your pocket is tight from money, then the problem is solved. When I found myself in such a situation, when the car would not start, I realized that I urgently needed a charger. But I didn’t have an extra thousand rubles to buy a charger. I found it on the Internet simple diagram, and decided to assemble the charger on my own. I simplified the transformer circuit. Windings from the second column are indicated with a stroke.

F1 and F2 are fuses. F2 is needed to protect against a short circuit at the output of the circuit, and F1 - against excess voltage in the network.

And this is what I got.

Now let's talk about everything in order. A power transformer of the TS-160 brand and a TS-180 can be pulled out from old black-and-white Record TVs, but I didn’t find one and went to the radio store. Let's take a closer look.

Petals. where the terminals of the trance windings are soldered.

And right here on the trance there is a sign indicating which petals produce what voltage. This means that when we apply 220 Volts to petals No. 1 and 8, then on petals No. 3 and 6 we will get 33 Volts and the maximum current to the load is 0.33 Amperes, etc. But we are most interested in windings No. 13 and 14. On them we can get 6.55 Volts and a maximum current of 7.5 Amperes.

In order to charge the battery, we just need a large amount of current. But our tension is low. The battery produces 12 volts, but in order to charge it, the charging voltage must exceed the voltage of the battery. 6.55 Volts will not work here. The charger should give us 13-16 Volts. Therefore, we resort to a very clever solution. As you noticed, the trance consists of two columns. Each column duplicates another column. The places where the winding leads come out are numbered. In order to increase the voltage, we simply need to connect two voltage sources in series. To do this, we connect windings 13 and 13′ and remove the voltage from windings 14 and 14′. 6.55 + 6.55 = 13.1 Volts. This is the alternating voltage we will get. Now we need to straighten it, that is, turn it into direct current. We assemble a Diode Bridge using powerful diodes, because a decent amount of current will pass through them. For this we need D242A diodes. A direct current of up to 10 Amperes can flow through them, which is ideal for our homemade charger :-). You can also buy a diode bridge separately as a module. The KVRS5010 diode bridge, which can be bought on Ali using this link or in the nearest radio store, is just right.

I think everyone who doesn’t remember remembers how to check diodes for functionality, here.

A little theory. A fully seated battery has a low voltage. As charging progresses, the voltage becomes higher and higher. Therefore, according to Ohm's Law, the current strength in the circuit at the very beginning of charging will be very large, and then less and less. And since the diodes are included in the circuit, a large current will pass through them at the very beginning of charging. According to the Joule-Lenz Law, the diodes will heat up. Therefore, in order not to burn them, you need to take heat away from them and dissipate it in the surrounding space. For this we need radiators. As a radiator, I ripped out a non-working computer power supply and used its tin case.

Don't forget to connect the ammeter in series with the load. My ammeter has no shunt. Therefore, I divide all readings by 10.

Why do we need an ammeter? In order to find out whether our battery is charged or not. When the Akum is completely discharged, it begins to eat (I think the word “eat” is inappropriate here) current. It consumes about 4-5 Amps. As it charges, it uses less and less current. Therefore, when the needle of the device shows 1 Ampere (in my case on a scale of 10), then the battery can be considered charged. Everything is ingenious and simple :-).

We remove two hooks for the battery terminals from our charger; in our radio store they cost 6 rubles apiece, but I advise you to take a better quality one, since these break quickly. When charging, do not confuse the polarity. It’s better to mark the hooks somehow or take different colors.

If everything is assembled correctly, then on the hooks we should see this signal shape (in theory, the tops should be smoothed, like a sinusoid). but can you show something to our electricity provider))). Is this your first time seeing something like this? Let's run here!

Impulses DC voltage They charge batteries better than pure direct current. And how to obtain a pure constant from an alternating voltage is described in the article How to obtain a constant from an alternating voltage.

Below in the photo the Akum is almost already charged. We measure its current consumption. 1.43 Amps.

Let's leave a little more for charging

Don't be lazy to modify your device fuses. Fuse ratings on the diagram. Since this kind of trance is considered power, then when the secondary winding, which we brought to charge the battery, is closed, the current strength will be crazy and the so-called Short circuit. Your insulation and even wires will immediately begin to melt, which can lead to dire consequences. Do not check the voltage at the charger hooks for a spark. If possible, do not leave this device unattended. Well, yes, cheap and cheerful ;-). If you really want to, you can modify this charger. Install short circuit protection, self-shutdown when the battery is fully charged, etc. At cost, such a charger cost 300 rubles and 5 hours of free time for assembly. But now, even in the most severe frost, you can safely start the car with a fully charged battery.

Those who are interested in the theory of chargers (chargers), as well as the circuits of normal chargers, then be sure to download this book on this link. It can be called the bible on chargers.

How to make a diode bridge

How to make a diode bridge to convert AC voltage to DC, single-phase and three-phase diode bridge. Below is a classic diagram of a single-phase diode bridge.

As you can see in the figure, four diodes are connected, an alternating voltage is supplied to the input, and the output is plus and minus. The diode itself is a semiconductor element that can only pass through itself a voltage with a certain value. In one direction, the diode can only pass through negative voltage, but not plus, and in the opposite direction, vice versa. Below is the diode and its designation in the diagrams. Only minus can pass through the anode, and only plus through the cathode.

Alternating voltage is a voltage where plus and minus change with a certain frequency. For example, the frequency of our 220-volt network is 50 hertz, that is, the polarity of the voltage changes from minus to plus and back 50 times per second. To rectify the voltage, direct the plus to one wire and the plus to the other, two diodes are needed. One is connected as an anode, the second as a cathode, so when a minus appears on the wire, it goes along the first diode, and the second minus does not pass, and when a plus appears on the wire, then, on the contrary, the first plus diode does not pass, but the second does. Below is a diagram of the operating principle.

For rectification, or rather the distribution of plus and minus in alternating voltage, only two diodes are needed per wire. If there are two wires, then there are respectively two diodes per wire, for a total of four and the connection diagram looks like a diamond. If there are three wires, then there are six diodes, two per wire, and you get a three-phase diode bridge. Below is a connection diagram for a three-phase diode bridge.

The diode bridge, as can be seen from the pictures, is very simple; it is the simplest device for converting alternating voltage from transformers or generators to direct voltage. Alternating voltage has a frequency of voltage change from plus to minus and back, so these ripples are transmitted after the diode bridge. To smooth out the pulsations, if necessary, install a capacitor. The capacitor is placed in parallel, that is, one end to the plus at the output, and the other end to the plus. The capacitor here serves as a miniature battery. It charges and, during the pause between pulses, powers the load while discharging, so the pulsations become unnoticeable, and if you connect, for example, an LED, it will not flicker and other electronics will work correctly. Below is a circuit with a capacitor.

I also want to note that the voltage passed through the diode decreases slightly; for a Schottky diode it is about 0.3-0.4 volts. In this way, you can use diodes to lower the voltage, say 10 diodes connected in series will lower the voltage by 3-4 volts. Diodes heat up precisely because of the voltage drop, say a current of 2 amperes flows through the diode, a drop of 0.4 volts, 0.4 * 2 = 0.8 watts, so 0.8 watts of energy is spent on heat. And if 20 amperes goes through a powerful diode, then the heating losses will already be 8 watts.

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Lada Priora Hatchback Rocket › Logbook › DIY charger

I bought a tester today and sat down to solder a charger from the remains of a subwoofer that had been torn apart earlier. A little theory for those who decide to repeat it. Charger. The power supply essentially consists of two modules. The first is a transformer, its task is to lower the voltage to the required 12 volts in our case. The second is a diode bridge; it is needed to convert alternating voltage to direct voltage. You can, of course, complicate everything and add all sorts of filters for light bulbs and devices. But we won’t do this because we’re too lazy.

We take a transformer. The first thing we need to find primary winding. We will supply it with 220 V from the outlet. We put the tester in resistance measurement mode. And it rings all the wires. We find the pair that gives the greatest resistance. This is the primary winding. Next, we call the remaining pairs and remember/write down what was called with what.

After we have found all the pairs, we apply 220 V to the primary winding. We switch the tester to the alternating voltage measurement mode and measure how many volts are on the secondary windings. In my case, it was 12 V at full speed. I took one with the thickest wires, cut the rest and insulated them

With that finished, let's move on to the diode bridge.

Removed 4 diodes from the subwoofer board

twisted it together into a diode bridge and soldered the connections

Diagram of a diode bridge and graph of changes in the structure of a sinusoid

this is what happened to me

All that remains is to connect everything and check for functionality

What happened to me

We turn it on and measure the voltage. To the left of the last photo there will be a minus on the diode bridge. On the right is a plus. We solder wires there that we will later connect to the plus and minus of our battery.

It is advisable to run one of the wires to the battery through a light bulb to protect the battery from an overdose of electricity

This is what happened in the end

And the last test with the connected LED strip

Desulfating scheme charger devices proposed by Samundzhi and L. Simeonov. The charger is made using a half-wave rectifier circuit based on diode VI with parametric voltage stabilization (V2) and a current amplifier (V3, V4). The H1 signal light lights up when the transformer is connected to the network. The average charging current of approximately 1.8 A is regulated by selecting resistor R3. The discharge current is set by resistor R1. The voltage on the secondary winding of the transformer is 21 V (amplitude value 28 V). The voltage on the battery at the rated charging current is 14 V. Therefore, the charging current of the battery occurs only when the amplitude of the output voltage of the current amplifier exceeds the battery voltage. During one period of alternating voltage, one pulse is formed charger then during time Ti. Radomkrofon circuits The battery discharge occurs during the time Tz = 2Ti. Therefore, the ammeter shows the average importance charger current, equal to approximately one third of the amplitude value of the total charger and discharge currents. You can use the TS-200 transformer from the TV in the charger. The secondary windings are removed from both coils of the transformer and a new winding consisting of 74 turns (37 turns on each coil) is wound with PEV-2 1.5 mm wire. Transistor V4 is mounted on a radiator with an effective surface area of approximately 200 cm2. Details: Diodes VI type D242A. D243A, D245A. D305, V2 one or two zener diodes D814A connected in series, V5 type D226: transistors V3 type KT803A, V4 type KT803A or KT808A. When setting up...

For the diagram "Charger for sealed lead-acid batteries"

Many of us use imported lanterns and lamps for lighting in case of power outages. The power source in them is sealed lead-acid batteries of small capacity, for charging which there are built-in primitive chargers that do not provide normal operation. As a result, battery life is significantly reduced. Therefore, it is necessary to use more advanced chargers that eliminate possible overcharging of the battery. The vast majority of industrial chargers are designed for operation in conjunction with car batteries, so their use for charging small-capacity batteries is inappropriate. Application of specialized imported microcircuits economically unprofitable, since the price(s) of such a microcircuit is sometimes several times higher than the price(s) of the battery itself. The author offers his own option for such batteries. Drozdov transceiver circuits The power allocated to these resistors is P = R.Izar2 = 7.5. 0.16 = 1.2 W. To reduce the degree of heating in the memory, two 15 Ohm resistors with a power of 2 W are used, connected in parallel. Let's calculate the resistance of the resistor R9: R9 = Urev VT2. R10/(Icharge R - Urev VT2)=0.6. 200/(0.4 - 7.5 - 0.6) = 50 Ohm. Select a resistor with the closest resistance to the calculated resistance of 51 Ohm. The device uses imported oxide capacitors. Relay JZC-20F with an operating voltage of 12 V. You can use another relay available in stock, but in this case you will have to adjust printed circuit board. ...

For the circuit "CHARGER FOR STARTER BATTERIES"

Automotive electronics CHARGER FOR STARTER BATTERIES The simplest charger for automobile and motorcycle batteries, as a rule, consists of a step-down transformer and a full-wave rectifier connected to its secondary winding. A powerful rheostat is connected in series with the battery to set the required current. However, such a design turns out to be very cumbersome and excessively energy-intensive, and other methods of regulating the current usually complicate it significantly. In industrial chargers for rectification charger current and changes its value sometimes apply SCRs KU202G. It should be noted here that the direct voltage on the switched-on thyristors at a high charging current can reach 1.5 V. Because of this, they become very hot, and according to the passport, the temperature of the thyristor body should not exceed +85°C. In such devices it is necessary to take measures to limit and stabilize temperature charger current, which leads to their further complication and increase in cost. The relatively simple charger described below has wide current control limits - practically from zero to 10 A - and can be used to charge various starter batteries of 12 V batteries. The basis (see. diagram) is placed triac regulator, published in , with additionally introduced low-power diode...

For the "Simple thermostat" circuit

For the "Telephone line holding device" circuit

TelephonyHold device telephone line The proposed device performs the function of holding a telephone line ("HOLD"), which allows you to hang up the handset during a conversation and go to a parallel telephone set. The device does not overload the telephone line (TL) or create interference in it. At the time of operation caller hears a musical background. Scheme devices telephone line hold is shown in the figure. The rectifier bridge on diodes VD1-VD4 ensures the required power polarity devices regardless of the polarity of its connection to the TL. Switch SF1 is connected to the lever of the telephone set (TA) and closes when the handset is lifted (i.e., it blocks the SB1 button when the handset is on-hook). If during the conversation you need to switch to a parallel telephone, you need to briefly press the SB1 button. In this case, relay K1 is activated (contacts K1.1 are closed, and contacts K1.2 are opened), an equivalent load is connected to the TL (circuit R1R2K1) and the LT from which the conversation was conducted is turned off. Amateur radio converter circuits Now you can put the handset on the lever and move on to the parallel TA. The voltage drop across the load equivalent is 17 V. When the handset is lifted on the parallel TT, the voltage in the TL drops to 10 V, relay K1 is turned off and the load equivalent is disconnected from the TL. Transistor VT1 must have a transmission coefficient of at least 100, while the amplitude of the alternating audio frequency voltage output in the TL reaches 40 mV. The UMS8 microcircuit is used as a musical synthesizer (DD1), in which two melodies and an alarm signal are “hardwired”. Therefore, pin 6 ("melody selection") is connected to pin 5. In this case, the first melody is played once, and then the second one indefinitely. As SF1, you can use an MP microswitch or a reed switch controlled by a magnet (the magnet must be glued to the TA lever). Button SB1 - KM1.1, LED HL1 - any of the AL307 series. Diodes...

For the diagram "Repairing a charger for an MPEG4 player"

After two months of use, the “nameless” charger for a pocket MPEG4/MP3/WMA player failed. Of course, there was no schematic for it, so I had to draw it up from the circuit board. The numbering of the active elements on it (Fig. 1) is conditional, the rest correspond to the inscriptions on the printed circuit board. The voltage converter unit is implemented on a low-power high-voltage transistor VT1 type MJE13001, the output voltage stabilization unit is made on a transistor VT2 and an optocoupler VU1. In addition, transistor VT2 protects VT1 from overload. Transistor VT3 is intended to indicate the end of battery charging. Upon inspection of the product, it turned out that transistor VT1 “went to a break”, and VT2 was broken. Resistor R1 also burned out. Troubleshooting took no more than 15 minutes. But with proper repair of any radio-electronic product, it is usually not enough to just eliminate faults; you also need to find out the reasons for their occurrence so that this does not happen again. Power regulator on ts122-20 As it turned out, during an hour of operation, moreover, with the load off and open case transistor VT1, made in a TO-92 package, was heated to a temperature of approximately 90°C. Since there were no more nearby powerful transistors, suitable to replace the MJE13001, I decided to glue a small heatsink to it. Photo charger devices shown in Fig. 2. A duralumin radiator with dimensions of 37x15x1 mm is glued to the transistor body using Radial teleconductive glue. The same glue can be used to glue the radiator to the circuit board. With a heat sink, the temperature of the transistor body dropped to 45.....

For the scheme "Charger for small-sized cells"

Power supplyCharger for small-sized cellsB. BONDAREV, A. RUKAVISHNIKOV MoscowSmall-sized elements STs-21, STs-31 and others are used, for example, in modern electronic wristwatch. To recharge them and partially restore their functionality, and therefore extend their service life, you can use the proposed charger (Fig. 1). It provides a charging current of 12 mA, sufficient to “update” the element 1.5...3 hours after connecting to the device. rice. 1 A rectifier is made on the diode matrix VD1, to which the mains voltage is supplied through the limiting resistor R1 and capacitor C1. Resistor R2 helps discharge the capacitor after shutdown devices from the network. At the output of the rectifier there is a smoothing capacitor C2 and a zener diode VD2, which limits the rectified voltage to 6.8 V. Next comes the source charger current, made on resistors R3, R4 and transistors VT1-VT3, and a charging end indicator, consisting of transistor VT4 and LED HL). As soon as the voltage on the charged element increases to 2.2 V, part of the collector current of transistor VT3 will flow through the indication circuit . T160 current regulator circuit LED HL1 will light up and signal the end of the charging cycle. Instead of transistors VT1, VT2, you can use two series-connected diodes with a forward voltage of 0.6 V and a reverse voltage of more than 20 V each, instead of VT4 - one such diode, and instead of a diode matrices - any diodes for a reverse voltage of at least 20 V and a rectified current of more than 15 mA. The LED can be any other type, with a constant forward voltage of approximately 1.6 V. Capacitor C1 is paper, for a rated voltage of at least 400 V, oxide capacitor C2-K73-17 (you can use K50-6 for a voltage of at least 15 V). Details installation...

For the circuit "THYRISTOR TEMPERATURE REGULATOR"

Household Electronics THYRISTOR THERMOREGULATOR The thermostat, the diagram of which is shown in the figure, is designed to maintain a constant temperature of indoor air, water in an aquarium, etc. A heater with a power of up to 500 W can be connected to it. The thermostat consists of a threshold devices(on transistor T1 and T1). electronic relay (on transistor TZ and thyristor D10) and power supply. The temperature sensor is the thermistor R5, which is included in the problem of supplying voltage to the base of the transistor T1 of the threshold device. If the environment has the required temperature, the threshold transistor T1 is closed and T1 is open. Transistor TZ and thyristor D10 of the electronic relay are closed in this case and the mains voltage is not supplied to the heater. As the temperature of the environment decreases, the resistance of the thermistor increases, as a result of which the voltage at the base of transistor T1 increases. Relay connection diagram 527 When it reaches the device's operating threshold, transistor T1 will open and T2 will close. This will cause transistor T3 to turn on. The voltage that appears across resistor R9 is applied between the cathode and the control electrode of thyristor D10 and will be enough to open it. Mains voltage through thyristor and diodes D6-D9 will go to the heater. When the temperature of the medium reaches the required value, the thermostat will turn off the voltage from the heater. Variable resistor R11 is used to set the limits of the maintained temperature. The thermostat uses an MMT-4 thermistor. Transformer Tr1 is made on a Ш12Х25 core. Winding I contains 8000 turns of wire PEV-1 0.1, and winding II contains 170 turns of wire PEV-1 0.4. A. STOYANOV Zagorsk...

For the "INTERCITY BLOCKER" scheme

Telephony LONG CITY BLOCKER This device is designed to prohibit long-distance communication from a telephone set that is connected to the line through it. The device is assembled on a K561 series IC and is powered from a telephone line. Current consumption - 100-150 µA. When connecting it to the line, the polarity must be observed. The device works with automatic telephone exchanges having a line voltage of 48-60V. Some complexity of the circuit is due to the fact that the operating algorithm devices implemented in hardware, unlike similar devices, where the algorithm is implemented in software using single-chip computers or microprocessors, which is not always available to a radio amateur. Functional diagram devices is shown in Fig. 1. In the initial state, the SW keys are open. The SLT is connected to the line through them and can receive a calling signal and dial a number. If, after picking up the handset, the first digit dialed turns out to be the exit index long distance communication, in the management circuit, a waiting multivibrator is triggered, which closes the keys and breaks the loop, thus disconnecting the telephone exchange. K174KN2 microcircuit The intercity access index can be anything. In this scheme the number "8" is specified. The time to disconnect the device from the line can be set from a fraction of a second to 1.5 minutes. Schematic diagram devices is shown in Fig. 2. The elements DA1, DA2, VD1...VD3, R2, C1 assemble a 3.2 V power supply for the microcircuit. Diodes VD1 and VD2 protect the device from incorrect connection to the line. Using transistors VT1...VT5, resistors R1, R3, R4 and capacitor C2, a telephone line voltage level converter is assembled to the level required for the operation of MOS chips. Transistors in this case are included as micro-power zener diodes with a stabilization voltage of 7...8 V at a current of several microamps. A Schmitt trigger is assembled on elements DD1.1, DD1.2, R5, R3, providing the necessary...

Very often there is a problem with charging a car battery, and there is no charger at hand, what to do in this case? Today I decided to publish this article, where I intend to explain all the known methods of charging a car battery, isn’t it interesting? Go!

METHOD ONE - LAMP AND DIODE

The light bulb is the most ordinary one, you can take a 40/60/100 watt lamp, the more powerful the lamp, the greater the output current, in theory the lamp is here only for current extinguishing.

The diode, as I already said, to rectify alternating voltage, it must be powerful, and it must be designed for a reverse voltage of at least 400 Volts! The diode current must be more than 10A! This is a mandatory condition, I highly recommend installing the diode on the heat sink; you may have to cool it additionally.

To increase the charge current, you can replace the incandescent lamp with another, more powerful load - a heater, boiler, etc.

METHOD TWO - BOILER

This method works on the same principle as the first, except that the output of this charger is completely constant.

The main load is the boiler; if desired, it can be replaced with a lamp, as in the first option.

You can take a ready-made diode bridge, which can be found in computer power supplies. It is MANDATORY to use a diode bridge with a reverse voltage of at least 400 Volts with a current of AT LEAST 5 Amps, install the finished bridge on a heat sink, since it will overheat quite strongly.

DO NOT USE powerful SCHOTTTKY diode assemblies from computer power supplies, they are very powerful, but the reverse voltage of these diodes is about 50-60 Volts, so they will burn out.

METHOD THREE - CONDENSER

I = 2 * pi * f * C * U,

where U is the network voltage (Volts), C is the capacitance of the quenching capacitor (uF), f is the alternating current frequency (Hz)