Enlarge circuit is converter of a kind of energy, it creates energy impossibly. Crystal dynatron is to use the little change of base electric current to control collector electric current to produce bigger change, valve and field effect canal are to use the little change of grid voltage to control plate electric current to produce bigger change, accordingly, field effect canal and valve are voltage control parts of an apparatus, and transistor is voltaic control parts of an apparatus.

 

Magnifier of enlarge circuit unlike is same, the written language that direct enlarge is viewed or object. Enlarge circuit is communication signal overlay over dc signal, by the change that communicates signal, cause the change of dc signal, repass load resistor, communicate the metabolic translate into of dc signal the change of signal. The crystal dynatron in enlarge circuit has effect of this kind of changeover namely, by base electric current little change controls the change with collector bigger electric current, was equivalent to magnifying base electric current.

 

There is dc part already in amplifier, have communication part again, go to the lavatory to analyse circuit, the method that often adopts dc composition place calls dc gateway, and the method that adopts communication signal place calls communication gateway. Because capacitance has the effect that lies between straight current communicating, when the picture sheds equivalent circuit continuously, answer to regard capacitor as open a way, other and changeless.

 

 

 

When analysing dc access, must return the negative pole of power source from the anode of power source, when forming to close access; communicates equivalent circuit in the picture, capacitor should regard short circuit as, direct current source because of its two upright voltage won’t change, fall without communication pressing generation, also regard short circuit as, other and changeless. When analytic communication access, need not each class repeats an analysis, should master whole signal however from why ab extra, pass yuan of what parts of an apparatus or appliance, produced what change, arrive at where finally.

 

Enlarge circuit has static state and trends normally status of two kinds of jobs. The static state is to show input signal is zero hour, direct current source offers an appropriate dc job voltage to each electrode of dynatron, make dynatron job is magnifying area, that is to say the exterior condition that dynatron magnifies is to launch a knot to slanting, market report knot slants instead. Trends is to show in the input of enlarge circuit end adds an input after signal, circuit of main analysis enlarge is right the enlarge ability of signal.

 

Because this is when analytic enlarge circuit, the trends after Xian Jing condition, analyse static dc access first namely, the working tension that sees canal of effect of transistor, valve, field is normal, after static work place is normal, analyse trends communication access again. And communication access and dc access are concomitant at same circuit in, they are contacted each other already, distinguish each other again. Communicating signal voltage is overlay on dc job voltage, and the influence that the communication function of circuit is nodded again by dc job and restrict. If shed bias voltage to be not stabilized continuously, or have trouble, communication access can be affected and appear breakdown.

 

In negative feedback circuit extent of occurrence output signal increases, the main reason of phenomenon of lack fidelity breakdown is, magnify negative feedback component damages in circuit, negative feedback effect disappears, make the gain of amplifier greatens, bring about output signal extent to increase. Whether does the negative feedback component in answering to check circuit mainly right now appear solder of open circuit, empty, resistor changes the phenomenon such as the value. If output signal to appear lack fidelity, demonstrative amplifier already worked in nonlinear area (saturation or off-state) , the job that should measure amplifier mainly hints tension, revive Fang of Qian of male of instrument of cent of Bian of course of study is owed the full front of a Chinese gown constant, whether does the parameter that puts bassoon produce change.