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.
Remote from the television station areas, in zones of uncertain reception of television signals of meter (MB) and decimeter (UHF) ranges have to install industrial television broadband antenna of the type ASP-8W, “LOCUS”, “DELTA”. Each of these antennas comes with a amplifier which can have a different magnification strength of incoming signals and is chosen for specific conditions of admission (for example, SWA14 gives signal gain 32 dB, SWA9000 — 38, SWA1L — 8 to 10 dB).
The safety device that signals the limit of the battery, must have for every modeller. The scheme of such a simple electronic device — figure 1. The unit is connected to the battery pack and press the button S2. If the supply voltage exceeds 10 V, relay K1. But as soon as this value is reduced to 10 volts, Zener diode is closed and relay K1 is de-energized. Contact K1.1 includes a signal lamp H1.