HF antennas. Schemes, articles of the Free Technical Library

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HF antennas. Schemes, articles, descriptions

Free library / Schemes of radio-electronic and electrical devices

HF antennas

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High voltage generator (Kirlian apparatus), 220/30000 volts

Section Power supplies. This device, which uses a regular car starter coil, produces voltages ranging from 5000 to 30000 V. The circuit generates pulsed high voltage at low frequencies and is suitable for observing or photographing the aura of small objects: coins, leaves, insects, other biological objects, including number of fingertips ... >>

Security system MICROALARM

Section Security devices and signaling of objects. The security system is designed to protect apartments, cottages, garages, etc. The basis of the OS is the 16F628A PIC controller. Arming and disarming is carried out using Dallas Semiconductor DS1990 electronic keys. The device operation algorithm is as follows: when the registered key touches the reader, and if the door sensor contacts are closed, the system becomes armed. This is signaled by the LED on the reader - it lights up. When the contacts open, if the security mode was not disarmed by touching the registered key again, the power load relay (PCH) is activated and the LED flashes. PCH allows you to control any load up to 120 VAC ... >>

Microbubble bath for PCB etching

Section Ham Radio Technologies. I do not think I will reveal a big secret if I say that several main factors affect the speed and quality of PCB etching. For example: if the etching process occurs in a solution of ferric chloride at room temperature, then it lasts, as a rule, from 40 minutes. up to 2,5 hours (depending on the saturation of the solution). If the solution is heated, then the etching process itself can be reduced in time by one and a half times. And in general, ideally, the solution itself should be periodically mixed, in which case the process is even faster. These factors directly affect the etching rate. If we talk about the quality of the boards, then this applies primarily to those radio amateurs who transfer the pattern to the textolite using a laser printer and an iron. Despite the fact that the toner adheres to the foil quite firmly, if the etching process is delayed in time, then ferric chloride still gets under the toner. In this case, the tracks are porous, which in turn degrades the quality of the board itself and the device as a whole. ... >>

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Articles on HF antennas

Articles on HF antennas; HF antenna circuits; descriptions of HF antennas: 170 articles

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Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

Karaoke by Apple 08.12.2022

Apple Music has a new feature. Essentially, Apple Music Sing is nothing more than karaoke reinvented. With it, you can jam, rap, mix and hum your favorite songs.

With the help of Apple Music Sing, users of the streaming service will be able to sing along to famous artists. Vocals are fully adjustable. This makes it possible to perform musical works in a duet with original performers. You can sing solo if you wish.

The feature launched in Apple Music is a karaoke experience with more features. For example, users can adjust the volume level of the original track. Due to this, you can easily sing a duet with any musician.

The full launch of Apple Music Sing is scheduled by the corporation at the end of December. Thus, the new feature will become available to users of the streaming service within a few weeks.

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