I am convinced that any device with power supply-battery flashlight will only benefit if you provide it a makeshift terminals, providing reliable electrical contact in the connection to the battery. Moreover, the time and cost it takes a bit.
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.
Utterly exhausted by his refrigerator, which has neither a hot day, then another “surprise” in the starting relay, was forced to ask for help in workshop. There categorically stated: burnt start winding, you need to change or rewind the motor. And when I calculated what it cost me… well, I ventured on a self-experiment with Read more…
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.
When 25 years ago on the pages of Newspapers and magazines began to appear about the creation of an electronic cybernetic machines are able to play dominoes, checkers, chess and other games, readers in different ways embraced the news. Alone, tossing up her hands in astonishment, and said, “just Think! What came to technique!” Other, moderately severe, people shrugged their shoulders: “Do scientists have nothing better to do?” “What are you — objected to them and others, not so serious, — let them enjoy themselves. It is necessary for scientists to have a rest after hard work”.
The principle of operation of my proposed homemade svetvincenat “Whelan” is forced Ventilation of the Lamp bulb and heat the bottom of the room with warm air by sending heat to the floor, which is the “waste” of the light source. Moreover, the “Whelan” cleans the air from dust. And the lifespan of the lamp filament is thus significantly increased.
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.