Mains power supply for electronic-mechanical watches with dial illumination. Encyclopedia of radio electronics and electrical engineering

Encyclopedia of radio electronics and electrical engineering / Power Supplies

 Comments on the article

The power source for household wall or desktop electronic-mechanical alarm clocks with the usual arrow dial for us is usually a 343 galvanic cell. However, there may be several such clocks in the house, therefore, naturally, the problem of replacing expired batteries periodically arises. In such cases, the galvanic cell can be replaced by a network power supply, as has been discussed repeatedly. But here another nuisance arises - stopping the "running" of the clock when the mains voltage fails.

More reliable and convenient to use are network power supplies with power storage devices in the form of small-sized nickel-cadmium batteries D-0.1, D-0.125. They will ensure the normal operation of the clock in both short-term and long-term power failures in the network.

The proposed power supply unit for electronic-mechanical clocks, the scheme of which is shown in Fig. 1, is an improved version of the units described in [3,4]. Its main difference is the ability to illuminate the dial in the dark. The design of the block corresponds to the dimensions of the galvanic cell 343 (R14), which allows you to quickly integrate it into the watch without any modifications.

Capacitors C1 and C2 perform the function of ballast reactive elements, extinguishing excess mains voltage. Their nominal capacitances determine the value of the current flowing through them. Due to the fact that the capacitors are included in different network wires, the voltage on all other elements of the block with respect to the ground does not exceed half the network. In addition, in the event of an emergency, these elements will be connected to the ground, the fault current will be limited and will not lead to serious consequences.

If the contacts of the SA1 switch are closed, then with a negative half-wave of the mains voltage on the upper (according to the diagram) wire, the VD2 diode will open and capacitors C1 and C2 will be charged through it. With positive half-waves, the capacitors will begin to recharge, the current will flow, first of all, through the open diode VD3 and the battery G1 and capacitor C3 will start charging. The voltage of a fully charged battery will be at least 1.35 V, and on the HL1 LED - about 2V. Therefore, the LED will begin to open and thereby limit the charging current of the battery. Therefore, the battery will always be in a charged state.

Thus, in the presence of voltage in the network, the clock is powered by it during positive half-cycles, and during negative half-cycles - by the energy stored by the battery G1 and capacitor C3. When the mains voltage fails, only the battery becomes the power source, the energy of which is enough for several days and even weeks of continuous operation of the clock - depending on the value of the current they consume.

The lighting of the dial is turned on by opening the contacts of the switch SA1. In this case, the charging and discharging current of the capacitors C1 and C2 flows through the filaments of the lamps EL1 and EL2, and they begin to glow. And the previously closed two-anode zener diode VD1 now performs two functions: it limits the voltage on the lamps to a value at which they glow with a slight undershoot (which increases their service life), and in the event of a filament burnout of one of the lamps, it passes the charge-discharge current through itself capacitors, which prevents disruption of the power supply as a whole.

Resistor R1 serves to discharge capacitors C1 and C2 when the device is disconnected from the mains.

All elements of the device, except for incandescent lamps EL1, EL2 and the SA1 switch, are placed on a printed circuit board made of double-sided foil fiberglass with a thickness of 1.5 ... 2 mm (Fig. 2). The shape of the board with the details on it resembles a 343 galvanic cell (Fig. 3), which can be inserted into the corresponding compartment of the watch. To simulate the contacts of the positive and negative electrodes of the battery, the printed conductors on both sides of the board are soldered along the edge with thin foil (for example, removed from the board blank). Capacitors C1 and C2, a battery are glued to the board, and then the rest of the power supply parts are soldered.

Capacitors C1 and C2 - K73 for a rated voltage of at least 300 V, C3 - K52, K50-6. The two-anode zener diode KS213B (VD1) can be replaced by two counter-series zener diodes D814D, KS213Zh, KS512A. Diodes VD2 and VD3 - any rectifier small-sized. The HL1 LED is any of the AL341 series, you just need to first select an instance in which the forward voltage at a current of 10 mA will be 1.9 ... mA) or similar low current. The SA2.1 switch can be of any design, it is only important that its body is reliably isolated from the mains.

In one of the input network wires of the device, for example, inside the plug X1, it is desirable to include a current-limiting resistor R_ogre (indicated by dashed lines in Fig. 1) with a resistance of 36 ... 51 Ohm for a dissipation power of 0.5 W, which prevents possible failure of the device elements at the time the power supply is connected to the network.

The assembled power supply can be placed in a cylindrical housing made of insulating material or simply wrapped with insulating tape. Incandescent lamps and a small-sized SA1 switch are installed in the most suitable place for them in the watch case.

Literature

1. Verhalo Yu. Power supply unit for "Glory". - Radio, 1992, No. 1, p. 67
2. Nechaev I. Power supply for electronic-mechanical watches. - Radio, 1990, No. 6, p. 76
3. Nechaev I. Power supply on optocouplers. - Radio, 1996, No. 6, p. 42
4. Karevsky V. A block that replaces the battery. - Radio, 1996, No. 6, p. 41

Publication: N. Bolshakov, rf.atnn.ru

See other articles Section Power Supplies.

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 EnCodec music format 06.11.2022 Meta, which owns Facebook, Instagram and WhatsApp, has unveiled a new AI-based audio compression method called EnCodec. It can compress audio 10 times better than MP3 format. The new method can be applied to real-time audio streaming, which can greatly improve voice quality over low-bandwidth connections, such as phone calls in areas with unstable connectivity. The method also works for music, so someday we will get really small music audio files with it. nCodec can compress audio 10 times more than the mp3 format at 64 kilobits per second without quality loss. Thanks to this, the file will take up 10 times less space on your hard drive with the same sound characteristics. The developers note that the neural network performs its task very well, and the human ear will not be able to catch the difference between the original and the recoded source. Now the new Meta technology remains in the research phase, but it points to good prospects where high-quality audio will use less bandwidth, which would be a great innovation for providers whose networks are overloaded with streaming media.

Other interesting news:

▪ Stimulation of the temporal cortex improves memory

▪ Smart T-shirt YouCare 5G

▪ Chimpanzee language

▪ Helmet-wearing cyclist takes more risks

▪ Changing red blood cells to activate the immune system against covid

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the site Reference materials. Article selection

▪ article Fragments of old generations. Popular expression

▪ article A furniture upholsterer co-authored what discovery in medicine? Detailed answer

▪ article Strangulation and respiratory failure. Health care

▪ article Why are you making noise at me in vain, birches? Encyclopedia of radio electronics and electrical engineering

▪ Article How much vitamin C is in an apple? Chemical Experience

Leave your comment on this article:

All languages ​​of this page

Arabic	Hebrew	Polish
Bengali	Hindi	Portuguese
Chinese	Italian	Spanish
English	Japanese	Turkish
French	Korean	Ukrainian
German	Malay	Vietnamese

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

www.diagram.com.ua
2000-2024