1. Common-emitter biasing
Consider Figure 1, set VCC = 10 V and find the conditions where the collector’s DC voltage is at mid-supply (e.g. 5 V).
List out the unknown quantities in this circuit first, then click
-
RC
-
RB
-
β
-
VBE (or IS and VT)
-
also keep VCC symbolic
-
Use (symbolic) circuit analysis to find VC,
-
then fix a few numbers (VCC = 10 V, β = 100, and IC = 0.893 mA) and solve for the resistor values.[1]
-
Solve for how VC changes when β varies over the range 15—450 with these resistor values.
VC =
2. Setting DC bias conditions
There are several common ways to get the DC bias conditions setup so that the transistor “idles” in the middle of the forward-active mode range. They all have various advantages and disadvantages.
- https://www.allaboutcircuits.com/textbook/semiconductors/chpt-4/biasing-calculations/
-
Discussion of several biasing schemes and their circuit equations.
2.1. Sony XDR F1HD audio amplifier
Page 2 of day06_handout-orig.pdf.
Sony_XDR-F1HD_audio-amp.pdf is a color version showing the Service Manual's expected DC node voltages.
