Concept
e-learning. It means that in the amplified circuit, the output signal is not complete, real amplification, but more less, this is distortion. There are a variety of distortion, this is a form of distortion.
Overcoming measures
Since the threshold voltage of the transistor is not zero, such as a general silicon triode, the NPN type is turned on at 0.7V, which is in the dead zone in 0 ~ 0.7. However, the input signal waveform cannot be fully simulated, and the PNP type is less than -0.7V is turned on. For example, when the sine wave of the input AC, two tubes between -0.7 to 0.7 cannot be turned on, the output waveform pair input waveform It is said that this is distorted, that is, it is crossing.
Measures to overcome the disturbance of crossing is: avoiding the dead zone voltage zone, so that each transistor is in a micro-conduction state, once the input signal is added, it immediately enters the linear work area
Provided to transistor static bias make it three ways : (1) The bias voltage is generated by the voltage drop of the diode and the resistance; (2) generates a bias voltage by using the V BE to enlarge the circuit to generate a bias voltage using a pressure drop on the resistor.
Duecent the distortion appears in the B-class amplifying circuit, the distortion of the amplification circuit is the least 10%, and the efficiency is less than 10%, and the class B has a dazzling but its efficiency is high, so the Alan amplification circuit appears. It is higher than the extraction efficiency, which is smaller than the distortion of B.