Application of load lines to transistor amplifiers
R. Lowe, D. Nave · 1973
Imagine a power transistor connected in its common-emitter configuration as shown in the circuit of figure 5.28. By manipulation of the variable resistors R 1 and R 2 , current into the base may be set to any convenient value. If now the resistor R 3 is varied over its maximum range to control the positive collector potential, corresponding values of V CE and I C can be recorded. When plotted on a graph, these figures represent a static output characteristic for this transistor. By repeating the experiment for different settings of base current, a whole family of curves can be plotted as shown in figure 7.1.