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Hits:3152 Shortwave antenna
The antenna is a 10-element Log-yagi (Fig.1), calculated UA3THQ and modified by me.Fig.1Specifications:Lбума = 7000 mmG28=9 db F/b=30 dbG24=6 db F/b=20 dbG2l=8,l db F/b=24 dbMaterial: tube D16T with a diameter...
Read moreHits:493 House, garden land, hobby
Honeybees live on Earth for over 10 million years. And of course, have tried to adapt to the environment in the wild, but not in home... From hibernation, they often...
Read moreHits:456 Clocks, timers, relays, load switches
Presents the photosensor circuit intended for indication purposes. Scheme the left side is active during the day ( the relay should work), in the circuit shown on the right -...
Read moreHits:595 Audio
The following diagram is the schematic diagram of Active Tone Control circuit, or we often call this circuit as “ACTOR”. The circuit is quite simple, easy build and inexpensive, you...
Read moreHits:532 Audio
For some time now, there have been a number of tape cassette decks available at low prices from mail order businesses and electronics retailers. Such decks do not contain any...
Read moreHits:935 Television and video
Proposed in [1] the amplifier is a field effect transistor with Schottky barrier (MESFET) was tested for the reception of weak TV signals and has shown fantastic results. So, barely...
Read moreHits:1065 Television aerials
UHF antenna described in the article A. Manakova, can be improved by adding three more elements. The gain of the modified antenna has increased significantly, which gives a great advantage...
Read moreHits:556 Lighting
DescriptionThis circuit is intended to let the user turn off a lamp by means of a switch placed far from bed, allowing him enough time to lie down before the...
Read moreHits:449 Power supplies
The old film-viewing device, which is not to be applied by direct purpose, it is easy to alter in regulated power supply with protection against overloads and short circuits. For...
Read moreHits:688 Television aerials
Often in practice there is a problem of unification of the two antennas of different channels on one feeder. This can apply the generic scheme shown in Fig.1. Fig. 1Coil...
Read moreHits:465 Power supplies
DescriptionIs the battery empty, or is there something wrong with the device? That’s always a difficult question when your walkman or some other battery-powered device appears to be dead when...
Read moreHits:472 House, garden land, hobby
The principle of operation is based on measuring the q-factor and inductance of the coil when near to a conductive metal surface.This simple device can measure the thickness of insulating...
Read moreHits:532 Shortwave antenna
The described antenna can be useful for application in cities with dense development. It is a wire frame with a perimeter at two wavelengths. The proposed location of the antenna...
Read moreHits:4419 Shortwave antenna
GP AT LOW FREQUENCY RANGES Interesting design shortened GP for Amateur bands 40 and 80 meters invited David Reid (PA3HBB/G0BZF). A detailed description of the antenna and the...
Read moreHits:500 Television and video
The input impedance of bipolar transistors at microwave frequencies is the unit of Ω and has an inductive component. Therefore, with the direct connection of a coaxial cable with wave...
Read moreHits:506 Filters and matching devices
A notch for a narrow frequency band of a few per cent or even less normally requires close-tolerance components. At least, that’s what we thought until we came across a...
Read moreHits:576 Power supplies
As a guide, a one-inch reed switch with 40 turns reliably switched on with the current flowing through a 150-watt lamp (approx. 625 mA) but larger reeds may require more...
Read moreHits:433 Power controllers, thermometers, heat
DescriptionBelow is a thermostat circuit I recently built to control a 1300 watt space heater. The heater element (not shown) is connected in series with two back to back 16...
Read moreHits:524 Lighting
DescriptionEvery self-respecting DIYer makes his own electronic dice with LEDs as spots. Then you don’t have to throw the dice anymore – just push the button. The electronics also ensures...
Read moreHits:1363 Metal detectors
The detectors on the beats are not very sensitive in the search for metals with a weak ferromagnetic properties, such as, for example, copper, tin, silver. To increase the sensitivity...
Read moreHits:763 Medicine
A sedentary life, illness, and sometimes just laziness, our muscles tend to atrophy. Decreases the blood supply to the muscles and organs. Biologically active points (acupuncture points) lose contact with...
Read moreHits:505 Power supplies
Many modern circuits tend to work from a single supply voltage of 3V. But often they need a virtual earth at half the supply voltage for efficient operation. The splitter...
Read moreHits:1499 Power supplies
Attention radio Amateurs will be designing the power supply for home lab. The advantage of this PSU that don't need an additional winding on the power transformer. DA1 chip single-supply...
Read moreHits:797 Telefonie
We offer telephone switchboard (aka micro-PBX) is a a device that allows you to connect one telephone line to up to five devices (without their mutual influence on each other)...
Read moreHits:534 House, garden land, hobby
In the artificial cultivation of mushrooms in the greenhouse you want to support specific humidity of the substrate with mycelium, pouring it in small portions water and prevent waterlogging. Start...
Read moreHits:507 Lighting
Had dinner, turned on the TV and settled down on the couch by the light ordinary crystal chandeliers. Bulbs and chandelier sparkle and hurt the eyes, screen "glare"! Even one...
Read moreHits:5379 Electronic devices
Motorists know how important proper installation of the ignition timing fuel in the cylinders of the engine carburetor. To do this, use strobe lights. In the article by P. Bialiatski...
Read moreHits:596 Indicators, detectors
I have made a large number of detectors microwave field in different designs and after article in "RL" No. 11/92, decided to share its experience in this area.First, in the...
Read moreHits:405 House, garden land, hobby
Here’s a twist to the age-old game of noughts and crosses. Instead of pen and paper, it uses nine 10mm tri-colour LEDs arranged in a 3 x 3 grid. One...
Read moreHits:813 Other
Indicates the basic integrity of a printed board, Self-powered - 3 to 30V rangeThis little circuit indicates the basic integrity of a printed board, detecting 0V, positive supply voltage from...
Read moreHits:3462 Shortwave antenna
Antenna Beverage or, as it is called, the antenna is a traveling wave (ABC), is widely used in professional radio. Most transoceanic QSO on 160 meter ham radio operators is...
Read moreHits:525 Power controllers, thermometers, heat
Although integral type timer 555 is primarily designed for chronologic schemes, but this is in conjunction with a thermistor having a negative T. C. S. can also be used to...
Read moreHits:704 Lighting
Especially designed for Christmas tree lamps, Replaces old thermally-activated switchesThis circuit is intended as a reliable replacement to thermally-activated switches used for Christmas tree lamp-flashing. The device formed by Q1...
Read moreHits:699 Medicine
Water containing ions of silver ("silver" or "living" water), has found application in medicine and in everyday life, and its useful properties described in the literature. Silver water can be...
Read moreHits:581 Power supplies
DescriptionHere is a simple but inexpensive inverter for using a small soldering iron (25W, 35W, etc) In the absence of mains supply. It uses eight transistors and a few resistors...
Read moreHits:529 Telefonie
Universal integral type 555 timer has another use -- in cheap musical synthesizer that plays a musical phrase from simple songs. It uses two timers: one generates the rhythm, and...
Read moreHits:723 Clocks, timers, relays, load switches
The proposed device is designed to protect equipment that consume DC voltage significant pulse current (USC, transceivers, etc.). The device disconnects the load in cases of excessive raising or lowering...
Read moreHits:437 Audio
This is the circuit diagram of electronic hearing aid featured with sensitive sound detection and energy saving, so this hearing aid will work in the long term with a 9V...
Read moreHits:599 Audio
To listen to television broadcasts on the headphones, not necessarily to pull away from the TV wire communication line. Help out the proposed wireless system (it was described in article...
Read moreHits:724 Antenna amplifiers
The kit to receive satellite TV programs includes a parabolic antenna, which is installed so that fell into the line of sight from the satellite, a step-down Converter and the...
Read moreHits:470 Indicators, detectors
The security of many electrical devices depends today on the availability of an earthed mains outlet. We should remember that these are connected to the frame or to the metal...
Read moreHits:734 Audio
It is known that for many motorists machine turned into something more than just a means of transportation. After all the person conducting the wheel a few hours a day...
Read moreHits:1135 Shortwave antenna
On the construction of the attention of the reader antenna was told on the radio 10-15 years ago ham V. Volia beach (UA6DL), for which the author is very grateful...
Read moreHits:5144 Shortwave antenna
About the height of antenna installation When choosing the design of transmit-receive antennas for Amateur radio stations in the shortwave has to take into account many factors...
Read moreHits:509 Indicators, detectors
It is not always immediately obvious whether a power-consuming appliance is switched on or not. Examples are the lamp in the attic or the shed, or electric heating in an...
Read moreHits:732 Shortwave antenna
Description shortwave antenna "IIIDX antenna operating in the bands 80, 40, 20 and 15 m published by the American shortwave W3JHR. The antenna is a vertical pin height of...
Read moreHits:3093 Electronic fuel injection
The fuel injection system "Motronic" is a combined system with distributed injection, i.e. at each cylinder has a separate atomizer. Each of the primary nozzles is controlled individually e-management unit...
Read moreHits:611 Lighting
In frequently visited areas to save energy, convenient to use capacitive relays for lighting control. When you enter the room, if necessary to turn on the light, go close to...
Read moreHits:538 Lighting
The problem of the durability of incandescent lamps, which sometimes blows at the moment of their inclusion in the network remains relevant. Some solutions described in the proposed materials....relay and...
Read moreHits:466 Bells and audio simulators
I lay imported electronic wrist watch in metal case with a faulty indicator. Names hours a lot of this type (for example, "Montana"), but they're all the same. At the...
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