Usually automatic device switch on and off the Christmas tree lights in leaps and bounds, without changing the brightness. But the electronic switch scheme is presented in figure — does not have this drawback. The basis of his work is based on the principle of beats that occur between the frequencies of the mains and generator. The latter is a multivibrator transistors T1, T2. It generates rectangular pulses with a frequency of (100 ± Δ) Hz (100 Hz is the fundamental frequency of the multivibrator, And the frequency of the beating, which switch lamp garland which is in the range of 0.1—8 Hz). Adjustment of the burning time of the lamps is variable resistor R6 “Smoothly” and R7 “Rough”.
SMOOTH SWITCH
The light on the dash must have heard many. A pistol or shotgun just like the real thing, the rings of a target with a ten in the middle. Yes, but “bullets” are not the same. Pulled the trigger and the target affects short flash of light. And the brighter dalnoboynie weapon. The light beam of the flash lamp to “shoot” at a target even from a distance of 25 m. This corresponds to one of the distances sports bullet shooting.
This switch Christmas garlands periodically includes four groups of lamps. The switching frequency can be changed within wide limits by the variable resistor R5 (see diagram).
Simple dual-band receiver of direct amplification on a hybrid chip К237ХА2 can collect even a novice hobbyist. Moreover, the sensitivity and selectivity it even higher than the equivalent discrete components. And to make it easy.
Probably you happen to see this picture: all the appliances in the apartment turned off, and the meter disk rotates slowly. It turns out that the culprit door electric bell: its primary winding permanently connected to the network.
In the design of devices and equipment before the radio often question about their design: sometimes they place boards and panels of their devices in boxes that slides, fishing gear and other containers. Ham D. Plewinski offers as buildings to use more modern products — cases videokasset: they have a low cost; plastic from which they are made, can be easily processed.
Revision of power supply EPS-35. Every radio Amateur, equipping a workplace, in its own way solves the problem of providing it with power supply (SP). Some prefer powerful UI with an output current 10 and 20 a, And someone is satisfied with a simple and low-current (up to 2). The taste and color, as they say, no friends. From my point of view, home laboratories should have a SP with output current not less than 5 and the overload protection on the output.
Usually they work, if it is correct to type the code on the keypad. Electric locks, which are placed in this article, operate on a different principle. The key for them is a small socket with the pins, for example, finger lamp. Socket is the base — it installed schema key. When enabled, a lock is triggered. And, as we have commotional lead wires, to reveal the secret of the castle will not succeed.
I work as an electrician. This profession is serious, requires not only deep knowledge in this field, but also special care with electricity trifled with. I have to work in different conditions—indoors, and outdoors in any weather. Here without nice and friendly equipment assistants can not do. So I try to keep up with the technology of today, follow the latest developments in the technical literature, including in popular science. Do not bypass the attention and homemade. I learned a lot of useful information from publications in the magazines “modelist-Konstruktor”, “Radio”, etc. One of my first homemade probe, the design of which was published in the “Modeller-designer” № 5 for the year 1990.
Monophonic electronic musical instrument (see figure) is assembled on a single chip К176ЛА7 containing four two-valve “AND—NOT”. On D1.1 is made the generator of frequency vibrato. The oscillation frequency at its output is 5-8 Hz. For valves D1.2 and D1.3 tone generator, and the D1.4 — the generator of high frequency oscillations. Thanks to our latest AMY can be used as a prefix to any radio receiver having a medium wave range.