There is a whole class of electronic devices that operate in standby mode, “waking up” only for a short time to perform their tasks, such as apartment bell, simple security system, automatic watering installation, houseplants and some other such devices in order to save electricity, it is desirable decrease in voltage when they are “resting.”
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.
often need Amateurs with a passion for designing low-frequency amplifiers. But in the sale they are not always. The solution? To make a simple potentiometer with taps. For this it is necessary to remove the cover and remove the axle with the slider. Then with an awl to puncture the plastic covering the hole in Read more…
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.
The device is useful for a model fire truck and a guard system. The intervals between the signals and their duration is controlled by changing values of electrolytic capacitors C1, C3, fixed resistors R2, R4 (see diagram). Sound effects you can Supplement the indicator light, replacing the resistor R3 with a bulb from a pocket Read more…
What is the kit-the fan does not dream to collect small-sized power source? But here everything depends on the power transformer: it-largely determines the dimensions of the power supply. If you try to make a transformer with a minimum size of, for example, with a magnetic core Ш12Х12, provided that the voltage of 220 V, the number of turns of the primary winding will be approximately 7600.
In recent years, and became noticeable interference in a household outlet, requiring protection home electronic equipment TVs, home audio, computers. These impairments lead to “tearing” of the image on the screens, heard the clicks and POPs from the speakers, “sboyat” digital devices. It is especially annoying when this happens while recording any programs.
