(The end. Start at # 1 ’03)
needed for anyone who is keen on constructing of measuring equipment and equipment for radio control models. Simple circuit universal wavemeter, shown in figure, is a conventional crystal radio set, whose output is headphones included the arrow measuring device ИП1 with the DC amplifier transistor T1.
In the old days, when required to perform switching in the electric circuits when the voltage rises to a certain threshold, resorted to the use of polarized electromagnetic relay. However, the substantial size and weight, lack of reliability of the kinematics and contact pairs severely limited the use of these devices. Now in their place came a miniature non-contact thingies called discs. This four-layer semiconductor diodes whose structure is like a two transistor: p-n-p and n-p-n type, with the base of one is connected to the collector of the second, forming the internal positive feedback (Fig. 1).
“For the treatment of infield has decided to replace the tiller internal combustion engine electric. Already got polutoraterabaytny the motor. But it is three phase. How to connect to the network, where only one phase and “my best”?
Viewers living in areas of new buildings high-rise buildings and besides, near the television station, I recommend to get a homemade antenna-loop. It works reliably even when the so-called “strong reflections” television signals and preventing screen ghosting of the image.
Hams know how sometimes when soldering they do not have a third hand to fix a small detail. At the time it was proposed many devices that can help in such a situation (see, for example, the magazine “modelist-Konstruktor” No. 10’1996). In particular, I use a fixture, which is made in just a few seconds.
Informing about the occurrence of an event, people often use sound signals. Usually they have the character of a continuous sound “one note” annoying “beep-beep” or howling siren with a periodically varying frequency. Generators of electric vibrations, producing these signals is also straightforward. They are based on one-two multivibrators, which makes the structure very simple, accessible to even beginners repetition hams.
Who used a portable transistor radio, know how, over time, decrease the sensitivity and loudness of the radio, begins to “float” the rate of advance of the tape in the music player…
Electricity is steadily going up. So now even avid spenders are forced to take care of her savings, the benefit — there is a very wide selection of devices designed to save valuable kilowatt hours. Its rightful place is here and homemade machines off “extra” loads. It is gratifying that among the most interesting of them — the development receiving a “ticket to life” in the pages of “Modeller-designer” (see, for example, publications in № 4’89, 6’91, 9’92, 1’95, 7’2001 of the journal).
Summer — time for vacation and travel. During this period, there is a special need for a universal power supply for various mobile (and not only) household appliances.