Op-Amps and Linear - Example 1-1

Does anyone still have "Op-Amps and Linear Integrated Circuits" 013630328 and can answer Example 1-1 (b)?

At point "(b)" the author suddenly seems to pull 25mv out of the air:

re = 25mV / IEma = 25mV / 0.998mA = 25.3 ohms

Where the freek does the 25mV come from? It must be really obvious or I am just daft.

From the text:

Rc=2.2k, Re=4.7k, Rin1=Rin2=50 ohms, +VCC=10V,

-VEE=-10V, and the transistor is CA3086 with BetaAc/Dc = 100, and Vbe=0.715V typical.

(a) Determine Icq and Vceq values (this is ok) (b) Determine the voltage gain

"(b)" is what I am having difficulty with.

"(a)" was calculated as Icq = 0.988 mA Vceq = 8.54V

Figure 1-2 is roughly (use fixed font for viewing):

+VCC +-------+----------+ | | Rc Rc | | +------o vo o------+ | | +----Q1 Q2------+ | | E1 |E2 | Rin1 +--------+---------+ Rin2 | | | Vin1 RE Vin2 | | | Gnd -VEE Gnd

Where Vin1, and Vin2 are signal generators. I am unable to point to any freely downloadable "browses" of the page in question. In the hardcover 3rd edition, the exmample 1-1 is on page 25.

I can only conclude that the author thought it so obvious that he didn't see the need to include where this 25mV came from.

Snark