Since ancient times people admired the music box. Their creation was only very skilled mechanics, who had besides an ear for music. Now the progress of technology made it easier. Electronic box whose schema is shown in figure 1, may collect even the ham is not very high qualifications. But a musical ear is still required.
The proposed remote control system (remote control) is executed in the form of attachment to the radio commercial production. It allows you to control ten different loads with up to eight fixed channels (the first pressing — on, second — off) and two not fixed (the operation is possible only when the button is pressed).
Devices for influencing the so-called biologically active points (BAP) are known to many. Including those created by radio Amateurs. Circuitry underlying some BAT-stimulants, saw light in the pages of “Modeller-designer” (see “modelist-Konstruktor” No. 1 and 3 in 1998). However, to implement them was proposed, as a rule, “miscomputing” database. Well, if to approach from positions of today, when even personal supercomputer are not uncommon?
Commonwealth sports and equipment… When it comes to this topic, we are Olympic records with their fantastic results and sophisticated instruments, able to capture such results.
Pushkin “Ah, summer red, I would love you, if not for the heat, and dust, Yes mosquitoes, Yes flies” not to recall with the advent of the hordes of winged insects that spoil our mood more than heat and humidity. And then remember the promotional video: in the fight with the flying vermin are becoming increasingly prevalent electronic protection. A few behind the effectiveness of chemical pesticides, it is more gentle to the environment, and this is now of the essence.
In Amateur radio practice, there are situations when 9-volt DC source you need to obtain 12, and then a higher output voltage. Bail in such cases can I designed a compact transformerless adapter. Made on the basis of two or three common chips and four transistors, it will allow first to improve the initial voltage of approximately 17 V, and then to output the desired 12 V. And stable.
Recently there is a rapid displacement of the cassettes compact discs (CD). Among the reasons for this and the continuous increase of requirements to quality of sound reproduction and virtually unlimited service life “compacts”, and reducing the value gap between them and the tape carriers of audio information. So, in June 2001, the market price of one CD with modern recordings is consistent with a cost a half to two cassettes. However, equipment to play music CDs is still very expensive and not everyone can afford its purchase.
For its production you will need two capacitors, a resistor and phone capsule (see diagram). Removing the insulation pad under the membrane of the phone parts are mounted directly in the capsule. Check the transistor is connected to the terminals of ALL the circuits. Occurs phone the sound vibrations talk about the health of the transistor. About its amplification factor β can be judged by the intensity of the sound: loud sound — high β, the weak — β low.
With the calculation of the resonant circuits (filters) have to face almost every radio Amateur. It is proposed to sub-contract the performance of this work a personal computer, using the program, interface is understandable and accessible to almost anyone. It all comes down, essentially, to the answers to the questions that are displayed on the monitor screen.
will inform you as soon as will fall the first drops of rain or humidity exceeds the norm. Device “look” and the fluid level in the reservoir tank.