The scheme is simple electronic guard device published the magazine “Funkamateur” (GDR). Across the doors of the protected object stretched thin wire. Until he is whole, the tension on the bases of the transistors VT1—VT3 are few and they are closed. In case of wire break on VT1 through a resistor R2 receives the bias voltage, and this semiconductor device is opened. Now, through a chain of R2—R4, the transistor VT3 will get more offset. Relay K1 will work, and its contact system will include a siren, a buzzer or a lamp. Moreover, the elimination of wire break will not change the situation is to disable the watchdog is possible only with the switch ЅА1.
THE “GUARD” DOORS
The Romanian magazine “Technium” offers a diagram of the electronic timer operates on the principle of the 5-minute hourglass clock every minute. The indication to carry out the LEDs. Such a device will find use in a home darkroom, sports training and rhythmic gymnastics. If the time interval exceeds 5 minutes, the device as a normal hourglass, you can restart and continue counting. Here’s how it works.
It never hurts to have your own car, in addition to the cigarette lighter socket, and even first connector, adapted to USB or even mini USB. Such adapters are useful in many cases, for example, to power peripheral equipment of PC, charging mobile phones, video recorders of events and everything is designed under USB power. This is quite possible.
Electric hand drill machine (or drill) there are many home craftsmen. But its opportunities will be wider if it is to provide a speed controller. In this case, the tool, in addition to its direct purpose, can be used as a screwdriver, and as a machine for winding coils. In particular, the design of the boring machine of IE-1019А allows you to embed an electronic controller in her butt — in the place where is located the entrance of the condenser, and the start button and variable resistor to set the handle of the tool.
Automatic device can be used in various models, toys that when meeting with obstacles will change their movement, as well as in everyday life (villages, for example, in the chair the lights went on in the lamp, the music began, earned the fan); to turn the light on in the premises (hallway, room, pantry); for the car alarm.
Nice in the dark frosty evening to sit by the radiant heat of the heater. But it becomes more comfortable when in it, like in a real fireplace, flickering “flame” and crackling “wood”. However, the industrial designs, simulation of burning firewood slowly, and all attempts to improve the installed impeller foil give only partial improvement results.
Repair of electronic devices in radio is associated primarily with the need to restore the holes and the possibility of damage to conductor paths of printed circuit boards. We offer universal soldering iron with suction device, solder and interchangeable tips will allow to replace the radio quickly and efficiently.
Not long ago, musical instruments even pop bands — be it saxophone, violin, accordion, piano, double bass and even a drum — gave his listeners a natural, “natural” sound. Today music has become different — is now in Vogue “electronic” sound.
During the experiments, building various electronic projects there is often a need for a DC source of relatively high capacity. For example, the battery voltage of 4.5 V is composed of three elements of “373.” To do this, you can put them in the original container tape out cut Velocimetry (see “M-K”, 1986, № 4), bonding like candy wrappers, wrapped in heavy paper (“M-K”, 1988, № 6), or dock in a unit with paper capsules-“shirts” from the same items (“M-K”, 1989, № 11). But still to provide a sufficiently reliable contact in such cases is not always possible. That is why many are still doing the old-fashioned way — connect the elements with each other lengths of wire with rations.