In 1877, a German (more precisely, Saxon) engineer, Kurt Siegel founded a manufacturing plant in St. Petersburg for the production of machines, appliances, and accessories for the water and gas industries. The company produced bathroom fixtures, gas lighting, plumbing, laundry equipment, and so on. After the 1917 Bolshevik Revolution, the entire Soviet industrial infrastructure was nationalized, and the Siegel plant became known as "Hydraulics" (Гидравлика).

In 1946, the plant began developing electric timepieces and was again renamed to reflect its new profile: Electric Timepieces (=Clocks and/or Watches) Plant ("Electric Timepieces Leningrad", EChL, Russian ЭЧЛ). The impetus for this change was the post-war importation (within the framework of post-war reparations) of precision mechanical timing devices from the German company Strasser & Rohde. These timepieces were shipped to the USSR as finished assembly kits, with minimal manufacture and/or fine-tuning required.

From 1946–1966, the plant produced a large range of electro-mechanical clocks which were installed atop high-rise buildings in Moscow and the Palace of Science in Warsaw, throughout the Kremlin Palace of Congresses, and in schools, factories, metro stations, and other public areas. The time intervals counters at the stations of all subways of the USSR were manufactured at EChL. When the world's first Soviet artificial Earth satellite was launched, it was tracked using numerous instruments, including those created at the EChL. Later, the factory's focus broadened to include multifunction chronometric devices and other precision measurement instruments. These devices, meant to measure time more precisely than any other, were used in navigation systems and in nuclear power plants.

Over the years, the plant's products have become more and more complex. The old name no longer corresponded to the production profile, so in 1975 the "Electric Timepieces Leningrad" was formally renamed into the Leningrad Experimental Plant of Electronic Time Devices "Chronotron". In the 1970s-90s, the plant produced electronic automated chronometric systems with a complex structure and with automatic correction by radio signals of the exact time. They are used in airports, spacecraft, and strategic weapons control systems.

At present, Chronotron continues to produce various precision time devices for use in public places and at various facilities, and implements a number of city clock programs in St. Petersburg based on the latest technical solutions.

During the 1950s, Electric Timepieces Leningrad plant was also participating in a side project of assembling mechanical watches made from parts manufactured at other factories. This began with partnerships at Uglich and Penza Watch Factories and the production of Zvezda wristwatches for women. These EChL-assembled Zvezdas are distinguishable from their Uglich and Penza counterparts only by the tiny inscription at the bottom of the dial, which reads ЭЧЛ Ленинград ("EChL Leningrad"). Also, the production of dials for the Pobeda, Mayak and others watches, also marked with EChL, was launched. All watches were assembled on the basis of third-party movements.

In the 1960s and 1970s, Electric Timepieces Leningrad formed an even-closer partnership with the Petrodvorets Watch Factory (Raketa). Beginning in the early-1960s, Petrodvorets provided EChL with complete movements and parts for a new line of mechanical wristwatches. All components for these watches were manufactured at Petrodvorets Watch Factory; only final assembly took place at Electric Timepieces Leningrad. These EChL/Petrodvorets hybrid watches were branded Svet (Свет, meaning "light"), and were identical to their Raketa counterparts, save for the printing on the dial. For example, here are the Raketa and Svet watches with the same dials, as well as the Raketa movement installed in the Svet:

On absolutely identical watches, there are also the inscriptions Mayak and Start — they do not differ in anything else. The EChL's Svet mainly used three Raketa movements: 2603 "Pobeda" (16 jewels), 2609 "Russia" (16 jewels) and 2609 NA "Flat Russia" (19 jewels).

Notably, Svet watches made during this time bore the factory logo on the dial: a pentagon with ЭЧЛ (EChL) stamped inside. The Svet watches continued to be produced for several years after 1975, but due to the change in the name of the plant, they were already without the EChL pentagon on the dial. Then the production of wristwatches was discontinued — according to Andrey Krukovich, the last Svet model with caliber 2609 NA was discontinued in 1979.

Little-known fact — Svet watches were produced not only in Leningrad, but also... in Chistopol!

This rare specimen was produced at the Chistopol Watch Factory. Such a Svet with the black dial was intended for the military, but it also appeared on the free market. Since 1969, all watches produced in Chistopol had the Vostok brand, and since then Svet has been produced only in Leningrad.

On the Internet you can find information that Svet watches were also produced at the 1st and 2nd Moscow Watch Factories. Most likely, this is a delusion — the production of watches under this brand is not confirmed by data from the history of either one or the other factory. The movements produced by one of these factories (as well as ZiM), which are sometimes found inside the cases of Svet watches, can be confusing. But, most likely, this is only the "creativity" of a repairmen — what was at hand was put instead of the broken original movement. In addition, small deliveries of movements from Moscow factories to the EChL could be carried out within the framework of intra-industry cooperation (this was common in the USSR).

A completely new Svet caliber 2609 with an original strap from the old exhibition of the Petrodvorets Watch Factory museum:

Well preserved gold plated EChL Svet:

Svet watches with different movements (first — a photo of the watch dial, then — the movement and (where available) the caseback and case details):

Svet watches are quite common on the Internet. Here, for example, a large number of vintage Svet watches for sale (you can just study the photos:)). A link to the thread of the watch.ru forum dedicated to the Svet brand is given below in the Sources section.

Not only wrist watches were produced under the Svet brand. Here is a post from a forum of radio amateurs, which tells about the recently declassified underground special communications center (Russian language, but we only need photos actually). One of the photos shows two clocks of the clock system with the recognizable Svet logo:

These are primary (reference, highly accurate) clocks. Two of them are there for duplication, in case of failure of one (the clocks show different times or, rather, do not run — which is typical:)). The facility was commissioned in 1966, so the year of manufacture of the clock system is the same or slightly earlier.

Well, here's a rare Svet table clock:

In the Alternative Watch History of Russia, the Svet brand also appeared — and also in the early 1960s, in St. Petersburg (the city, of course, did not become Leningrad, and ceased to be Petrograd soon after the First World War). But unlike our reality, the brand exists to this day, and the watches are produced at the same Siegel plant. Actually, Svet is the name of the watch division of the Siegel concern. The origin of the name Svet (Light), as in our reality, is lost in the 60s — there are various theories explaining the choice of this word, including conspiracy ones:) The slogan of the brand is "Let there be Svet (Light)!"

The brand occupies the middle-priced segment, mainly producing watches of classic design with a reference to the 60s-70s of the XX century. Traditionally, the Raketa movements produced by partners and neighbors from Petrodvorets are mainly used... That is, Peterhof, of course!