Busy with household chores or interesting conversation, we forget, for example, on a boiling kettle. Time to remind him maybe a simple buzzer. However, the oscillators sound frequency (e.g. multivibrators) based on transistor logic or integrated circuits do not always meet their creators. The simplest devices give a smooth tone, barely visible against the background of everyday noise, and sudden and loud “beep-beep” of a more complex designs can scare.
We offer homemade household heat stabilizer can be used in incubators, dryers, fruit, mini-greenhouses etc. From existing analogues it is original schematic construction, maintaining the temperature with an accuracy of ±0.1 °C, tolerance with fluctuations in the AC 160 to 240 V, and can operate from a DC source with voltage up to 310 V. the Power regulated heater element can reach 750 watts.
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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.
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.
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.
Seed stations and seed agro-laboratories often calculate “manual. Manual labor is unproductive and tedious, especially if you need to count a large number of seeds. Counting on 10 thousand grains of wheat takes about three hours. And to make a mistake during manual account easily. However, this operation can be replaced by a method of weighing, but due to the difference in sizes of the seeds of error in this case reaches 30%.
A lot of interesting instruments created in radio school of the Gomel Palace of pioneers and schoolchildren named after V. I. Lenin. Here are some of them: pulse the flash and the instrument for testing high-power transistors developed by members of the group Valery Denisenko and Sergey Skruzny.
Analog IC К176ХА10 was developed as a combined that contains a standard power amplifier of sound frequency (umzch) and has long been undertaken by radio Amateurs on Board. With supply voltage 9 In it has an output of 0.7 W at the output, but… recommended by the manufacturers the option to include К176ХА10 has impressive size and value (with the condition playlist “bass”) is the oxide capacitor, the reliability of which by modern standards is poor.