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Acquaintance from radio by details


What only details will not be necessary for manufacturing offered designs! Here both resistors, and transistors, both condensers, and diodes, and switches... From variety of radio details it is necessary to be able quickly to distinguish on appearance necessary, to decipher an inscription on its( her) case, to define (determine) conclusions., how it to make, and will be briefly told below. More particularizes on radio details you will find in the description of designs self-made devices.

The resistor. This detail meets practically in each design. Represents porcelain  a core with an aperture (or core), on which outside a core with an aperture a most thin film of metal or soot (carbon). The resistor has resistance and is used to establish the necessary current in an electrical circuit. Recollect an example with the tank: changing a diameter of a pipe (the resistance of loading), is possible to receive this or that speed of a flow of water (electrical current of various force). Than the film on porcelain  a core with an aperture or core is more thin, the more resistance to a current. On the circuits the resistor is designated by the Latin letter R (from a word Resistance - to resist).

The resistors are be constant and variable. From constant use resistors such as MLT (metals a varnish   heat-resistant), WS (water-resistant resistance), ULM (carbon  a varnish small-sized), from variable - SP (resistance variable) and SPO (resistance variable volumetric) more often.
The resistors distinguish on resistance and capacity. Resistance, as you already know, measure in ohm, Kohm and Mohm. Capacity express in WATT and designate this unit by the letters VA. The resistors of different capacity differ by the sizes. Than more capacity of the resistor, the
is more his(its) sizes.

Resistance of the resistor put down on the circuits near to his(its) conditional designation. If resistance less than 1 whom, figures specify number Ohm without a unit of measurements. At resistance 1 whom and more - up to 1 ÌÎì specify number Kohm and put beside the letter "K". Resistance 1 MOhm and above express by number MegaOhm with addition of the letter "M". For example, if on the circuit near to a designation of the resistor is written 510, the resistance of the resistor 510 Ohm means. To designations 3,6 to and 820 to corresponds (meets) resistance 3,6 whom and 820 whom. The inscription on the circuit 1 M or 4,7 M means, that the resistance 1 MOhm - and 4,7 MOhm are used.
As against constant resistors having two conclusions, at variable resistors of such conclusions three. On the circuit specify resistance between extreme conclusions of the variable resistor. The resistance between an average conclusion and extreme changes at rotation acting outside of an axis of the resistor. And, when an axis turn in one party, the resistance between an average conclusion and one of extreme grows, accordingly decreasing between an average conclusion and other extreme. When an axis turn back, there is a return phenomenon. This property of the variable resistor is used, for example, for regulation of loudness of a sound in amplifiers, receivers, a gramophone.
The condenser. It is necessary to tell, that it is possible to see this detail, as well as resistor, in many self-made designs. As a rule, most simple condenser are two metal plates  and air between them. Instead of air there can be of porcelain, a mica or other material not conducting current. If the resistor passes a constant current, through the condenser it does not pass. And the alternating current through the condenser passes. Due to such property the condenser put there, where it is necessary to separate a constant current from variable.

As you know, at the resistor basic parameter - resistance, at the condenser - capacity. The condensers are be of constant and variable capacity. At variable condensers capacity changes at rotation acting outside of an axis. Except for these two types, in our designs one more version of condensers - tuning is used. Usually it establish in this or that device that at adjustment more precisely to pick up necessary capacity and more condenser to not touch. In amateur designs the tuning condenser quite often use as variable - it is cheap and is accessible. On the circuits the condenser is designated by the letter With (from a latin word Capacitor - store).
Unit of capacity - microFarada (MF) is taken for a basis in radioamateur designs and in the industrial equipment. But more often other unit - PicoFarada (pf), million share MF is used. On the circuits you will meet also that, and other unit. And capacity up to 9100 pf   inclusive specify on the circuits in PicoFarada, and more than - in MncroFarada. If, for example, near to a conditional designation of the condenser is written "27", "510" or "6800", capacity of the condenser accordingly 27, 510 or 6800 pf means. And the figures 0,015, 0,25 or 1,0 testify that capacity of the condenser makes the appropriate number MicroFarada.

It is a lot of types of condensers. They differ by a material between plates and design. There are condensers air, mica, ceramic etc. One of versions of constant condensers - electrolitics. Such condensers issue of large capacity - from 0,5 up to 68000 Mf.

On the circuits for them specify not only capacity, but also it is possible to use the maximal voltage, on which them. For example, it is necessary to take an inscription 5,0x10 In means, that the condenser of capacity 5 Mf on a voltage 10 V.
For variable or tuning condensers on the circuit specify extreme values of capacity, which turn out, if an axis of the condenser to turn from one extreme rule up to another or to rotate round (as at tuning condensers). For example, the inscription 5 - 180 testifies that in one extreme rule of an axis capacity of the condenser makes 5 pf, and in the friend - 180 pf. At smooth turn from one rule in another capacity of the condenser also will change smoothly from 5 up to 180 pf or from 180 up to 5 pf.




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