Useful tips - How to determine the polarity of a DC source without a device.

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 (C) RINDEX

 We are pleased to present you another new section.  it will contain
describe all sorts of useful little things that can help you in life.
So, we give the floor to the presenter of this column...

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 (C) MAL'S


 How to determine the polarity of the source 
                 DC without a device?
                                          

   In amateur practice, you can use the following methods:
bami:

   1. Warm water is poured into a glass and table water is dissolved in it.
a spoonful of table salt. Then the ends of the wires are lowered into the water,
connected to the battery terminals. The wire connected to the negative
battery terminal, bubbles will be released intensively
gas

   2. The raw potato tuber is cut into two parts and into one
parts from the cut side are stuck at a distance of 15-20 mm from each other
other wires from the battery terminals, stripped of insulation. About
wire connected to the positive terminal of the battery, potato
turns green.3. Two conductors connected to a higher source
tension is introduced into the candle flame. Flame under voltage
the spark plug will become low and wide, and on the negative electrode there will be a
a thin ribbon of soot curls around.

   4. For permanent use, you can make a simple indi-
Cator for determining the polarity of an unknown source. He is pre-
is a glass tube, closed with stoppers, with a
inserted into its electrodes (spiral holders), taken from
burnt out electric lamp.

   To fill the cavity of the tube, a solution of selenium is prepared.
three (1 part) in water in water (4 parts). To this solution add-
The same volume of a mixture of glycerin (5 parts) and a solution of fe-
nolphthalene (0.1 part) in wine alcohol (1 part).

   Such an indicator serves for years, giving a red color to
negative pole, and if the source voltage is alternating,
then a pink color appears on the two electrodes. To destroy
To color, just shake the tube.


			I wish everyone good luck!