Input and output buffer amplifiers. Buffer amplifier at op-amp. Get to the point

As a rule, garlands have a fairly simple design and typical faults that are easy to fix even without special skills and tools. But in some cases you may need a soldering iron and a multimeter. Therefore, you may still have to contact a radio amateur you know.

The cause of problems with a garland, like any electrical equipment, is the failure of one or more circuit elements. Everything is usually repaired by replacing a faulty part, which can be found in another garland or some broken equipment.

Careless handling of an electric garland can result in an electric shock or damage to the device. You perform all actions at your own peril and risk. Lifehacker does not bear any responsibility.

All electric garlands are arranged the same. In older models, these are light bulbs connected in one circuit that light up or blink when connected to the network. Modern ones add a controller for lighting in different modes and the light bulbs can be replaced with LEDs.

Instructions

Stock up on several garlands equipped with light bulbs with the same parameters. One of them will be a “donor” of lamps to repair the others.

After disconnecting from the network, open the controller. Check to see if any wires have come loose from the board. On one of its sides there are two contact points for connecting the power cord, on the other there are five pads for connecting color channels. One of these sites is located away from the remaining four - the common wire of the channels is connected to it. Often, repairs are completed when the conductors that have been unsoldered from them are soldered to these pads. When you are finished using the controller, close it.

Some garlands are equipped with lamps that self-short-circuit when they burn out. The light bulb in which the short-circuiting device has been activated has less resistance than the working one, which is why the remaining lamps in the channel operate in forced mode. Therefore, burnt-out lamps in such a garland must be replaced with serviceable ones as soon as possible. They can be taken from the “donor” garland. Make the replacement by de-energizing the garland, carefully solder all connections and insulate them with several layers of electrical tape.

If there are no short-circuiting devices in the lamps, when one of them burns out, the entire channel goes out. It is clear that dialing each of them separately will take a lot of time, so you will have to use the iteration method. With the power turned off, cut the channel exactly in the middle. Ring sections of the canal from beginning to middle and from middle to end. Now it is clear which of them contains the burnt out lamp. This section can also be divided in half and both halves can be ringed, and so on until the burnt out lamp is found. Replace it by taking a serviceable one from the “donor” garland. After this, reconnect the wires in all the places where you cut them. Carefully solder and insulate connections.

Light bulbs pose a particular danger in a garland. When turned on, they instantly burn out, and the full network voltage begins to operate between the thread holders, which are not insulated in any way. Such lamps should be immediately replaced with working ones.

Never short-circuit a burnt-out lamp instead of replacing it with a new one, otherwise increased voltage will be applied to the remaining lamps in the channel and they will burn out faster.

LED garland repair has two features. The first of them is that the new LED must be turned on in the same polarity as the other diodes of the same channel (a rectifier is installed in the controller of any garland). The second feature is the need to connect a resistor in series with each LED. Its value should be the same as that of the resistors on the other diodes of the same garland. You cannot mix light bulbs and LEDs in the same garland, since the former have a rated current of usually 50 or 100 mA, and the latter - 20.

After completing the repair, before continuing to use the garland, be sure to carefully inspect it for the presence of uninsulated connections. Isolate them carefully.

Although the price of garlands is low, sometimes situations arise when you have to repair them. And there are not many opportunities here. Next we will talk about simple methods repair

Tips for operation and repair are usually given in abundance on back side beautiful packaging box. The process of replacing light bulbs is described in great detail, although there are no spare ones included. There are also a lot of safety warnings and instructions for using the garland.

One of the wonderful properties of such garlands is that after lying on a shelf until the next New Year, they most often do not want to light up, and they have to be repaired. Figure 1 will help explain how to do this.

All malfunctions of such garlands come down to three types: broken wires, loss of contact in the sockets, burnt out lamps. After they crushed the garland in their hands, shook it, felt all the cartridges, had a fight swear words and have not achieved results, you have to get down to business seriously.

To facilitate the procedure, the garland should be laid out on the floor, literally, as shown in Figure 1, and instrumental measurements should be taken. But first, lightly tug on the wires, it will suddenly fly out of the socket, try to tighten the light bulbs a little.

This is best done with the garland on, but don’t get too carried away, as you won’t crush the bulbs. Otherwise, you might just get an electric shock! The method is unsafe, but quite effective and efficient.

Figure 1. An example of repairing a New Year's garland

If these actions did not help, and the garland did not light up, then you will have to move on to instrumental measurements. First, the upper and lower (as in the picture) halves of the garland. Ring the half that turns out to be faulty several more times, each time reducing the length of the measured section by exactly half. This will greatly reduce the number of attempts. This is Magic force number two.

To check how magical it is, try folding a notebook or A4 sheet of paper in half ten times. You can even bend a whole newspaper, but it still won’t work, because two to the tenth power is 1024! This is exactly how many layers there should be in a folded sheet of paper. Therefore, you can argue with anyone about this “intellectual” exercise even on New Year’s Eve. All the same, victory will be yours. If you don't believe me, try it right now!

But, before “ringing” the entire garland with a multimeter, you should make sure that the wiring has not broken off right next to the outlet of the power plug. This is a fairly common defect, and not only in garlands, but in almost all plugs, especially with one-time sealing.

After the faulty “half” is found, all that remains is to check the light bulbs and soldering in the lamp sockets. From time to time high temperature the solders simply oxidize, or the wires break off, and they are quite thin, and here you go, the repair.

It happens that the New Year's garland itself fails, and it is clear that there is nothing to replace it with. It happens that weekends explode, leaving black spots of soot on the board.

Thyristors can be changed, fortunately, they are sold on radio markets and in online stores. The issue price is 13 rubles per piece. And this at a price new garland 38 rubles! Although, in fairness, it should be noted that there are similar garlands that are much more expensive. So all repair possibilities come down to finding broken wires, as described above.

Sampler for repairing garlands

Checking with a multimeter is undoubtedly good, but poking the probes of the device through the insulation of the wires is a thankless task. Probes specially created for this purpose will help speed up the troubleshooting process. The diagram of one of them is shown in Figure 2.

Figure 2. Diagram of a probe for repairing garlands

Working with the probe is very simple. You need to start with the wire of the garland that is included in the phase. In this case, if the antenna WA1 is subjected to an electric field, a high-pitched sound is emitted from the speaker BF1. When the antenna passes the break and moves to the side of the neutral wire, the squeaking in the speaker stops.

Here, as they say, options are possible. If you start with the neutral wire, then after a break in the garland it will fall under the antenna. phase wire, and naturally, the sound will appear. The BF1 speaker uses a DEM-4M capsule or a similar one with a coil resistance of 100…200Ω. Similar capsules are used in telephone sets.