This continues a series of blog posts on David Rutledge’s text, “The Electronics of Radio”, that I am studying while building the NorCal 40B transceiver. This series of posts will not be a review of the book, nor is it a assembly manual. Rutledge presents a series of problems at the each chapter that aid in understanding electronics and building the 40M QRP CW transceiver. I am going to try to go through all of these problems and document them here. All of these are titled similarly, so search for them that way. For what its worth, most people will want to skip these posts, they are really for my own self-education on electronics and may not make a lot of sense unless you have Rutledge’s book.

[The links to all problem solutions as I go through them will be posted here.]

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A.

v_i = 156 mV
v = 74 mV (R13 fully counterclockwise)
G_v(minimum) = v/v_i = 74/156 = 474.4E^-3
(NOTE: I do not think I used a large enough DC offset, thus the Gain results).

v_i (top trace), v (R13 fully counterclockwise)

v_i = 68 mV
v = 440 mV (R13 fully clockwise)
G_v(maximum) = v/v_i = 440/68 = 6.47

v_i (top trace), v (R13 fully clockwise)

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B.

R_{12+13(clockwise)} = 22.2Ω = R_emitter(min)
v_i(clockwise) = 156 mV

R_{12+13(counterclockwise)} = 518Ω = R_emitter(max)
v_{i(counterclockwise)} = 440 mV

Note: The gain calculated for the maximum resistance at the R13 potentiometer is 6.05. This is very similar to the measured gain of 6.47.

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C.

Vi at the maximum gain setting = 68mV

Miller Capacitance (C_m) = 26.9pF