IV characteristic curve of BJT

1. Common emitter connection

(1) Input characteristics

$$i_B=f(v_{BE}){|}_{v_{CE}=Constantnumber}$$

$v_{BE}$Gradually increase, the transmitting junction is forward biased and turned on, producing a larger current.
$v_{CE}$Gradually increase, make the collector junction from forward bias to reverse bias, enhance the ability to collect electrons, and take away the original $i_B$Current, $i_B$Decrease.
When $v_{CE}$Increase to a certain extent, the ability to collect electrons increases very little, for $i_B$The impact is also diminishing. So think $v_{CE}$The curves coincide when >1V.

(2) Output characteristics

① Amplification area The
collector junction is reverse biased, and the ability to collect carriers is very strong. The more carriers are generated by the transmitting junction, $i_C$Bigger.

② Saturation zone The
emission junction is positively biased, and the ability to collect carriers is small, even if $i_B$Increase, $i_C$Also not much increase.

③ Cut-off area The
emission junction is reversely biased, and there are few electrons reflected. No matter how the points change, no current will be generated.

2. Common base connection

(1) Input characteristics

(2) Output characteristics

3. Common collector

(1) Input characteristics

(2) Output characteristics

4. The influence of temperature on the characteristic curve

(1) For input characteristics

(2) To output characteristics