Every radio Amateur knows that without a source of constant and alternating stresses of different magnitudes in practical work is not enough. He needed to establish radiocontrole, repair equipment, charge batteries, test the motors and relays, to conduct physical experiments. All this is possible to do with a universal power supply, which we offer to the readers.
In this case doctors usually recommend to warm up the area of nose and the bridge of the nose with bags of hot sand or a medical reflector. But here’s the problem: the bag has to hold hands and to periodically change the sand cooled and the heat from the reflector heats not only the nose but the whole face, and even the light from the lamp is blinding. Heating pads, too uncomfortable — too big. But perhaps the most significant drawback of all mentioned devices is the inability to smoothly adjust the heating temperature.
It often happens when someone from the household forgets to turn the lights off in the toilet — he may be there without the use of a lot of hours. A simple automatic device which, when necessary, turns on the light in the bathroom, and when not — turn off. The electrical circuit of such device is presented in figure 1. It contains: a low-power transformer T1, rectifier VD1 — VD4, filter capacitor C1, two limit switches SB1 and SB2 relay K1. How the device works and how it performs its functions?
It is used in teaching music in rhythmic gymnastics, in experiments in physics etc. a Metronome, a scheme which offers Bulgarian journal “Radio Television Electronics” (see Fig.), gives not only audio but also visual signals. With the help of variable resistors R1, R2 their frequency change in the range of 40 to 200 cycles / min. which corresponds to the musical pace from “grave” to “Prestissimo”.
Every time, going to work in the morning, we try not to forget to turn off the apartment lights and appliances. Meanwhile, the function can be run machine consisting of three main blocks (Fig. 1): sensors, digital control unit and key. Here’s how it works.
A simple power control of the load can be made from industrial phase speed controller electric BUE-ЗВР1. This device has small dimensions 50×55 mm, excluding handles and a reversible switch. Its purpose is to regulate the speed commutator AC motors.
The vast majority of household electrical appliances aren’t grounded. At first glance, it is not necessary: the chassis devices are securely isolated from the network, and work with them, usually in dry areas with non-conducting floors. But to rely entirely on technique impossible. If the breakdown or damage to insulation — faulty device becomes a source of serious danger. Fuses are useless: they will not burn out until there is a short circuit.
Bought seedlings of two tree-eight-year. Roots are naked without earth. If it sticks? Put all the rules of farming. One soon began to show signs of life and the other is not. I waited two weeks. No movement of the kidneys. I decided to help her stimulation. Brought to the garden plot regulated power supply, multimeter. Plunged to the root of the tree a metal pin with a length of 400 mm (minus). The top of the tree connected to the power supply using the crocodile (“plus”). Turned on the power supply and gradually began to raise the current, but it is more 3 ua did not increase it was Thought that the venture won’t work.
Old things can be treated differently. For someone this “junk” is worthy only of the dump. But if we threw out less garbage, you see, and the ecology of the planet would not be so depressing. During regular maintenance the hostess decided to change the chandelier, and no amount of persuasion that it can be restored, didn’t help. One argument out of fashion. But to throw out the lamp I did not. Adding diffusers and associated parts, hid in the far corner of the pantry. We had to wait long.
Had dinner, turned on the TV and settled down on the couch by the light of an ordinary crystal chandeliers. Light bulbs and the chandelier sparkle and hurt the eyes, the screen “flashes”! Even one bulb is stopping! And no background light color TV to watch harmful to the eye. Had to cover the chandelier with a paper sheet. Watch TV easier, but it’s not the way out, and fire safety is thus broken! Maybe buy a table lamp, noble lamp, can light a candle. Each option has its pros and cons.