Improving the performance of electronic wristwatches. Scheme, description

Free technical library

ENCYCLOPEDIA OF RADIO ELECTRONICS AND ELECTRICAL ENGINEERING
Free library / Schemes of radio-electronic and electrical devices

Improving the performance of electronic wristwatches. Encyclopedia of radio electronics and electrical engineering

Free technical library

Encyclopedia of radio electronics and electrical engineering / Clocks, timers, relays, load switches

Comments on the article

Now a wide range of cheap watches are sold. They have typical flaws. So, the watch I bought with a calculator and an alarm clock had a very quiet signal and "ran away" up to 11 seconds a day.

After disassembly, the reason for the quiet sound became clear - there were printed conductors on the board in the corner for installing a surface-mount transistor. One output (emitter) was connected to the minus of the battery, the other (collector) - to the spring contact of the piezoelectric emitter, and the third (base) led to the clock chip. There was a jumper between the base and the collector. As a result, an alternating voltage with an amplitude of up to 1,5 V was applied to the crystal.

The refinement scheme is shown in fig. one.

Improving the performance of electronic wristwatches

Due to the lack of a planar transistor, a KT358A was installed, and its body was slightly filed. Inductor L1 is wound on a K8x2x0,08 ferrite ring with a wire with a diameter of 650 mm, the number of turns is XNUMX. It has been experimentally established that the more turns, the better. You can strengthen the output of a coil wound with such a thin wire in a known way: fold the end of the wire several times, burn the varnish with a match or lighter, and then clean it with a thin sandpaper or soldering iron on an aspirin tablet.

With the specified inductor, the signal amplitude reached 12 V and the sound was heard throughout the room. You can slightly change the tone of the signal by selecting a capacitor between the collector and emitter. The inductor is glued in a suitable place, and the jumper on the board between the base and the collector is cut.

The transistor closed well in the absence of a signal - the current consumption did not increase.

To adjust the clock, small capacitors are usually installed between the terminals of the quartz resonator and the common wire (or "plus" of the power source). The board has a pad for a surface mount capacitor. However, the installation of a capacitor did not practically change the speed of travel. When controlled with an oscilloscope, it turned out that the voltage amplitude at the other output of the quartz resonator is 4 times less ("cold" output). When a capacitor with a capacity of 15 pF was installed between this output and the "plus" of the power supply, the clock drift became less than 0,5 s per day.

On fig. 2 schematically shows the elements and pads.

Improving the performance of electronic wristwatches

Author: V. Ananiev, Yaroslavl

See other articles Section Clocks, timers, relays, load switches.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

Advanced Infrared Microscope 02.05.2024

Microscopes play an important role in scientific research, allowing scientists to delve into structures and processes invisible to the eye. However, various microscopy methods have their limitations, and among them was the limitation of resolution when using the infrared range. But the latest achievements of Japanese researchers from the University of Tokyo open up new prospects for studying the microworld. Scientists from the University of Tokyo have unveiled a new microscope that will revolutionize the capabilities of infrared microscopy. This advanced instrument allows you to see the internal structures of living bacteria with amazing clarity on the nanometer scale. Typically, mid-infrared microscopes are limited by low resolution, but the latest development from Japanese researchers overcomes these limitations. According to scientists, the developed microscope allows creating images with a resolution of up to 120 nanometers, which is 30 times higher than the resolution of traditional microscopes. ... >>

Air trap for insects 01.05.2024

Agriculture is one of the key sectors of the economy, and pest control is an integral part of this process. A team of scientists from the Indian Council of Agricultural Research-Central Potato Research Institute (ICAR-CPRI), Shimla, has come up with an innovative solution to this problem - a wind-powered insect air trap. This device addresses the shortcomings of traditional pest control methods by providing real-time insect population data. The trap is powered entirely by wind energy, making it an environmentally friendly solution that requires no power. Its unique design allows monitoring of both harmful and beneficial insects, providing a complete overview of the population in any agricultural area. “By assessing target pests at the right time, we can take necessary measures to control both pests and diseases,” says Kapil ... >>

Random news from the Archive

Yogurt can cure depression 13.03.2017

Everyone knows that yogurt is good for digestion, clear skin and shiny hair. But a new study by scientists at the University of Virginia School of Medicine also found that yogurt can treat depression. This creamy product contains lactobacilli, which can reduce blood pressure, stress and depression.

Experts have found that the amount of lactobacilli in the gut affects blood levels of a metabolite called kynurenine, which has been linked to depression. When lactobacillus levels in the gut are low, kynurenine levels rise, causing symptoms of depression. The findings improve understanding of the role of the gut microbiome in mental health, the researchers said.

During the tests, the researchers stressed mice and noticed that the main change in this case was the loss of lactobacilli in the intestines. This, in turn, led to symptoms of depression. However, when the rodents were given lactobacilli, their mental state improved.

Going forward, the scientists intend to study the effects of lactobacilli on patients with multiple sclerosis, a group in which this mental disorder is common.

Other interesting news:

▪ smallest satellite telescope

▪ Sun, alcohol and pedals

▪ Radar in the temple

▪ Malaria lures mosquitoes to humans

▪ Launch of the world's first floating wind farm

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ site section Power supplies. Article selection

▪ article Normal physiology. Crib

▪ article What did Alexandre Gustave Eiffel create? Detailed answer

▪ article Corydalis dense. Legends, cultivation, methods of application

▪ Loudspeaker Design article. Encyclopedia of radio electronics and electrical engineering

▪ article Norms of acceptance tests. SFXNUMX switches. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews