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Under the small-signal condition A small signal

high without adversely affecting bias stability.įigure 5.49 Linear operation of the transistor.of ? and RB (b) RB can be made large to keep.

Biasing Using a Constant-Current Source.

However, the value of RB determines the allowable.

RB provides negative feedback, which helps to.

Biasing Using a Collector-to-Base Feedback.

In almost total b-independence of the bias Ground, or to a grounded signal source, resulting Otherwise, the base can be connected directly to

Signal is to be capacitively coupled to the base. Using Two-Power-Supply Bias Scheme (withįigure 5.45 Biasing the BJT using two power.With the voltage divider supplying the base Single power supply (a) circuit (b) circuit Neitherįigure 5.44 Classical biasing for BJTs using a Result in wide variations in IC and hence in VCEĪnd therefore are considered to be bad. Using a degenerating RE to stabilize the biasįigure 5.43 Two obvious schemes for biasing theīJT (a) by fixing VBE (b) by fixing IB.Both result in wide variation in IC and hence in.Two obvious Bias schemes for BJT (Not so good,.The node voltages And the branch currents. Using Thevenins theorem to find out theĮx Assume ?100 for both Q1 and Q2.To verify which operation mode (active orĮx Assume ?100.Voltages at all nodes and the currents through The different modes of operation of the BJT.Įx With the above assumptions, let ?100, findĮx For a PNP BJT case. then by KCL, to solve the branch currentsįigure 5.32 A simple circuit used to illustrate.then by KVL, solve iB at first, and then to.If under active mode the terminal currents.The Key point to solve the DC solutions.High-Frequency Model 2.9 Frequency Response of Operation and Models 2.7 Single-Stage BJTĪmplifier 2.8 The BJT internal Capacitances and Chapter 02 Bipolar Junction Transistors (BJTs)Ģ.1 Device Structure and Physical Operation 2.2Ĭurrent-Voltage Characteristics 2.3 BJT as anĪmplifier 2.4 BJT Circuits at DC 2.5 Biasing in