What biasing is?

[MacIntoshCZ]

Hello,
i am reading art of electronics and i found term "biasing" (Biasing an emitter follower from a previous stage...).
I am from CZE, so dont exactly know what it means in this case. Google translator do not help. It doesnt make any sense for me.
ENG -> CZ (Biasing - předpětí)
CZ -> ENG (Předpětí - preload)
Thanks

 

[rjenkinsgb]

Having a normal value other than zero or neutral, as with "Political bias", favoring one party over another.

In electronics, such as using resistors to set the base voltage of a transistor or having an opamp input set to mid supply; the DC or idle operating levels.

It's a bias rather than a fixed voltage as it is changed by the signal passing through whatever.

 

[JimB]

Biasing con be considered as "defining the working conditions" of a transistor.

Example

If we connect a supply of say 10v to an NPN transistor, +ve to collector, -ve to emitter, there will be no current flowing in the emitter-collector circuit.
But if we put a small current into the base, a larger current will flow in the emitter-collector circuit.

We have now "biased" the transistor into conduction.
We could say that the transistor is biased to give 10mA collector current. (Or whatever value of collector current we have set).
The bias is the standing current before any signals are applied to the transistor.

Does this waffle help your understanding?

JimB

 

[MacIntoshCZ]

Does this waffle help your understanding?
JimB

Yes,thanks a lot.