and much of the advantage

брать ча́шку с ча́ем — take a cup of tea

брать кого́-л по́д руку — take smb's arm, slip one's arm through smb's

брать что-л себе́ — take / appropriate smth, make smth one's own

брать кого́-л на рабо́ту — employ smb; take smb on

брать кого́-л в а́рмию — enroll smb in the army

таки́х не беру́т в космона́вты — people like that are not admitted to the cosmonauts' squad

брать рабо́ту на́ дом — take one's work home

брать в пое́здку оди́н чемода́н — travel with one suitcase only

брать кого́-л на попече́ние — take charge of smb

брать на себя́ расхо́ды — finance / cover the expenses

сли́шком мно́го на себя́ брать — take too much on oneself, exceed one's powers

брать нало́г — collect a tax

ско́лько вы берёте в час? — what is your charge / price per hour?

брать ли́шнее — charge too much, overcharge

он берёт умо́м — he succeeds by dint of his wits

она́ берёт такти́чностью — the secret of her success is tact

она́ берёт умо́м, а не красото́й — it is her wit and not her beauty that puts her at an advantage

его́ берёт страх — he is in the grip of fear

его́ страх не берёт — he feels no fear

его́ берёт отча́яние — he is seized / overcome with despair

э́та винто́вка берёт на пятьсо́т ме́тров — this rifle has a range of five hundred metres

его́ пу́ля не берёт — bullets don't harm / hit him, he is invulnerable to bullets

брать впра́во — turn to the right

брать вле́во — bear left

брать такси́ — take a taxi

э́тот това́р пло́хо беру́т — this merchandise sells poorly

брать верх (над) — take / gain the upper hand (over), prevail (over)

брать за се́рдце — touch / move deeply

ста́рость берёт своё — old age tells

брать себя́ в ру́ки — pull oneself together, control oneself

импульсный источник электропитания с коммутацией тока на первичной стороне
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In primary switch mode power supplies, the AC mains voltage is first rectified and smoothed and then chopped ("switched"). Chopping means that the DC voltage is switched periodically at a frequency of 40 to 200 kHz using a power transistor.
In contrast to linearly regulated power supplies, the power transistor does not act as a variable resistor but as a switch instead. This generates a square-wave AC voltage that is transformed to the secondary circuit using a high-frequency transformer. In the secondary circuit, the voltage is rectifi ed and smoothed. The quantity of energy transformed to the secondary circuit is controlled, depending on the load, by varying the chopping rate. The longer the transistor is conductive, the higher is the quantity of energy transformed to the secondary circuit ( pulse width modulation).
Due to the use of high-frequency AC voltage, primary switch mode power supplies have the decisive advantage that their transformer can be of much smaller size than required for the transformation of low frequencies. This reduces the weight and the dissipation inside the unit. The effi ciency of these units is between 85 and 95 %. Since the output voltage does not directly depend on the input voltage, these units can be used for a wide input voltage range and can even be supplied with DC voltage. Furthermore, it is possible to buffer short-time mains voltage breakdowns up to 200 ms. However, the power failure buffering time is limited by the size of capacitor C1 since a longer buffering time requires a higher capacity and thus a bigger size of the capacitor. Especially in case of small power supplies this is not desirable.
Therefore, a practicable compromise has to be made between the size of the power supply and the buffering time.
Primary switch mode power supplies can be used for all purposes. For example, they are suitable for the supply of all kind of electronics as well as for electromechanical applications.
[ABB]

Тематики

• источники и системы электропитания

EN

• primary switch mode power supply