ABSTRACT
The graph of output current against input current of a BJT is almost a staight line. compare this with the graph on p. 63 where the gradient of the curve increases with increasing input voltage.
This is the kind of circuit used for measuring the forward transfer characteristic of a BJT
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BJT amplifiers
The ratio between the two (or the slope of the curve) is known as the small signal current gain, symbol hfe. In this example:
hfe = 3.84/10 [mA/µ A] = 384 The grain for the BC548 is often listed as 400
(but see below). Note that the graph is almost a perfect straight line.
