Garland fault finder with indicator light. Scheme, description

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ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
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Garland fault finder with indicator light. Encyclopedia of radio electronics and electrical engineering

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Encyclopedia of radio electronics and electrical engineering / Beginner radio amateur

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As soon as you bring the device to a faulty garland lamp, the finder's LED will immediately flash. The field effect transistor VT1 (Fig. 1) acts as a sensor that "captures" even a very weak electric field strength. In the place of a burned-out lamp, it will be the largest, since one of its terminals has a phase wire of the lighting network, and the other has a zero wire. Therefore, when a field-effect transistor of the finder is next to such a lamp, the resistance of its drain-source section will decrease so much that transistors VT2, VT3 will open. The HL1 LED will flash.

Garland Fault Finder with Indicator Light
Ris.1

The field effect transistor can be any of the KP103 series, and the LED can be any of the AL307 series.

Instead of an LED, a miniature incandescent lamp with a voltage of 1,5 or 2,5 V and possibly less current consumption is suitable. Bipolar transistors can be any other low-power silicon or germanium structures indicated on the diagram and with the highest possible current transfer coefficient. Resistors - MLT-0,125.

When mounting a field effect transistor, it is placed horizontally on the board, and the gate terminal is bent so that it is above the transistor case. If during the operation of the finder its excessive sensitivity is revealed, the output of the shutter is shortened.

Author: D.Bolotnik

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The secret of ancient wine 28.02.2015

In Israel, for the first time, grape seeds from the Byzantine era were found. This grape was used to make "wine from the Negev" - one of the best and most famous wines in the Byzantine Empire.

The charred seeds, more than 1500 years old, were discovered during excavations in the ancient city of Halutz in the Negev, during joint research by the University of Haifa and the Israel Antiquities Authority.

"Today, European grape varieties grow in the Negev, and the Negev vine has been lost to the world. Our next task is to recreate the ancient wine, and perhaps in this way we will be able to reproduce its taste and understand what made the wine from the Negev so good," - said Haifa University professor and expedition leader Guy Bar-Oz.

Archaeologists knew about "wine from the Negev" or "wine from Gaza" - as it was called by the port from which the drink was transported to all corners of the empire - from written sources of the Byzantine period. It was believed that this wine was of the highest quality and was very expensive, but, unfortunately, not a drop of it has survived to this day, so we do not know what is the reason for its exceptional taste. Earlier, during excavations in the Negev, archaeologists discovered terraces on which grapes were grown, wineries in which wine was made, and vessels in which it was stored and exported, but grape seeds could not be found before.

Halutza, in its heyday, was the most important city in the Byzantine Negev. The stone houses of Halutsa, as elsewhere in the Negev, did not survive to this day: the buildings were dismantled into stone for many centuries. But, as often happens, the rarest finds were waiting for archaeologists in a landfill. According to the professor, the city dumps have remained virtually intact and now mark the boundaries of the ancient city. Landfills are so prominent in the area that they can be seen on satellite images, for example, using Google Earth. Pottery and coins found in the rubbish deposits show that they accumulated mainly in the sixth and seventh centuries AD, when the city was at the peak of its economic growth. Since the decline of Halutza in the middle of the seventh century, which occurred for reasons not yet entirely clear, organized waste collection ceased, perhaps the city itself was abandoned around the same time.

In the rubbish layers, the researchers found a particularly large number of fragments of ceramic vessels that were used for storage, cooking and table setting. Among them were also vessels from Gaza, in which they kept ancient wine from the Negev. Archaeologists have also found a large number of remains of biological origin: the bones of fish from the Red Sea, the remains of mollusks and crustaceans from the Mediterranean Sea.

Hundreds of tiny charred grape seeds stood out among the finds. This is the first direct evidence that grapes were grown in the Western Negev in antiquity. Finding the pits was not easy: researchers used soil sifting and flotation (washing) for the first time.

The next stage of the study will be DNA sequencing of the bones. This will determine the origin of the vines. Scientists do not yet know what grapes were grown in the Negev. Were the vines "imported" - French or Italian (European varieties are grown in the Negev today) - or were they of local origin. European grape varieties require a lot of water, which creates difficulties in the local arid climate. Today, there are fewer problems with this, they are solved with the help of modern technologies. But it is unlikely that around 1500 years ago the ancient inhabitants of the Negev solved them so easily. Perhaps the secret of wine from the Negev lies precisely in the fact that some special grape variety was grown here, which could grow well in the arid conditions of the Negev.

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