diff --git a/09_bjt_small_signal.tex b/09_bjt_small_signal.tex
new file mode 100644
index 0000000000000000000000000000000000000000..4b98eaf2b9cabc3d254e5c5176a7120b17fd25c6
--- /dev/null
+++ b/09_bjt_small_signal.tex
@@ -0,0 +1,34 @@
+\section{BJT small signal}
+\begin{center}
+    \begin{circuitikz}
+        \draw (0,2) node[left]{B} to [short,i=$i_b$ , *-] ++(1,0)
+        to [R,l=$r_{be}$,v=$v_{be}$] ++(0,-2)
+        to [short] ++(2,0)
+        to [cI,l_=$g_mv_{be}$,i<=$$] ++(0,2)
+        to [short] ++(2,0)
+        to [R,l=$r_{o}$] ++(0,-2)
+        to [short] ++(-2,0)
+        to [short,i=$i_e$,-*] ++(0,-1)node[below]{E}
+        ++(2,3)
+        to [short,i<=$i_c$,-*] ++(1,0)  node[right]{C};
+        % to [open,v_=$v_{ce}$] ++(0,-2);
+    \end{circuitikz}
+\end{center}
+
+\subsection{Transistor amplifiers, 2 step analysis}
+
+
+\begin{enumerate}
+    \item DC analysis
+          \begin{enumerate}
+              \item Get DC equivalent circuit (rm C, cc L)
+              \item Find OP using large signal model of transistor
+          \end{enumerate}
+    \item AC analysis
+          \begin{enumerate}
+              \item Get AC equivalent circuit (cc C, rm L)
+              \item Replace transistor with small signal model
+              \item Use small-signal AC model to find characteristics
+              \item Combine AC and DC analysis
+          \end{enumerate}
+\end{enumerate}
diff --git a/format.tex b/format.tex
index f24f6aa72273100ebadbc9329111df990ab86a57..45caad0fa7ef1784775089b1b5bb8bfc00d3941a 100644
--- a/format.tex
+++ b/format.tex
@@ -29,7 +29,7 @@
 
 
 
-\usepackage[european]{circuitikz}
+\usepackage[european,straightvoltages]{circuitikz}
 \usepackage{tikz}
 
 \usepackage{url}
diff --git a/semiconductor_summary.tex b/semiconductor_summary.tex
index 12bfc3c1869e0d9a43841daba10d4186c55b12fc..e2751efb1570fa54cbf9ab0a9b3c066550565a02 100644
--- a/semiconductor_summary.tex
+++ b/semiconductor_summary.tex
@@ -38,12 +38,13 @@
 
 \tableofcontents
 
-\include{01_fundamentals}
-\include{02_carrier_transport}
-\include{03_pn_junction_basics}
-\include{04_pn_junction}
-\include{05_pn_junction_bias}
-\include{06_pn_junction_diode}
+\include{01_fundamentals.tex}
+\include{02_carrier_transport.tex}
+\include{03_pn_junction_basics.tex}
+\include{04_pn_junction.tex}
+\include{05_pn_junction_bias.tex}
+\include{06_pn_junction_diode.tex}
 \include{07_diode_applications.tex}
-\include{08_bjt}
+\include{08_bjt.tex}
+\include{09_bjt_small_signal.tex}
 \end{document}