Ham radio

Smoothly change the brightness of room lighting or hall comfortable with the thyristor voltage regulator (see Fig.). The scheme allows you to adjust the load voltage ranging from 220 V to 0, 25 W to 1 kW. But if the thyristors to supply the radiators, then it will increase to 1.5 kW. The main elements of the regulator, the thyristors V1, V2, included a counter each other and parallel to the load. They alternately pass current in one or in the other direction.

In many cities on the lively streets and highways have electronic thermometers. Some of them, with light of a mercury column, like an ordinary thermometer, the other made in the form of a digital display. To make such devices themselves is not available to everyone. But the simplified design of the indicator can be manufactured by the forces of the circle of automation students.

Many families today live in multi-storey buildings and use of household washing machines. Everyone who connects this machine (for electrical switchboards and sanitary communications), knows how important both of these operations. In particular, when defective connection drain pipe to the housing ganovim the pipes of communication may occur leakage of water which not only spoil the mood and the interior, but also bring tangible expenses payment of repairs to neighbors below. Even when quality of connection clamps, tightening the corrugations, and pipes drain hose of the washing machine, we recommend that from time to time to check for leaks and if necessary tighten.

When installing the radio a lot of time to spend on processing wires. First of all you need to remove the insulation, clean, tinned with stinging, and then proceed to soldering. Except for this the soldering iron, necessary lies, cutter and blade. And together with the isolation often cuts off part of the wire cores, n then have to start all over again. I propose a simple adaptation to the soldering iron. The eye eliminates unnecessary hassle, save time, improve the quality of construction works.

Radio, about which we tell, collected under the scheme direct gain works in long ranges (2000 — 740 m or 150 — 400 kHz) and medium (200 — 550 m or 520 — 1600 kHz) waves. Despite its relative simplicity, it has a sensitivity sufficient for admission to the internal magnetic antenna stations, remote distance up to 250 — 300 km With outdoor antenna reception range even more.

To calibrate, to establish or verify the performance of the radio equipment in the frequency range of 1-75 MHz allows this device. His scheme (Fig. 1) comprises a generator-the”type” with capacitive connection is made to the transistor V1. The oscillator frequency and its harmonics determine the replacement of quartz resonators B1, connected via connectors X1—X3.

In the fourth issue of the journal for the year 1978, published schemes of electric locks with a “secret”. They all work well, but they, in my opinion, there is one drawback: the locks can not be powered from a DC source. I propose a scheme for electronic lock, the key to which is the resistor. Here’s how it works. When the terminals X1 and x2 (see diagram) connect the resistor R2, transistor V1, the base voltage goes negative, opens and relay K1 is triggered.

Chandelier, sconce or a floor lamp in every house. They often burn on several lamps. Do I need it? Not always. And here is the owner of such a lamp becomes involuntary “waster” of electricity. But only because turning off “unnecessary” lights are not available. However, you can add a third wire. But in flats with concealed electrical wiring immediately raises a problem: where to spend it. And that’s where the master comes home… diode.