Exercise 3.4 Biasing a clap switch circuit

The circuit schematic below — a clap switch circuit [3] — does not indicated whether $T_1$ and $T_2$ are BC548 A, B or C. Especially the current gain $\mathit{\beta fe}$ can be anywhere between 110 and 800.

a)

Derive, from the schematic, the supply voltage $V_{\mathit{CC}}$ for the (left hand side of the) circuit, e.g. for the part left of $R16$.

b)

Derive an expression for $V_{C,T1}$ as a function of $V_{\mathit{CC}}$, resistor values $R2$, $R3$ and current gain $\mathit{\beta fe}$.

c)

Show that $T_1$ and $T_2$ are not properly biased for all of the transistor types (A,B,C).

d)

Calculate the bias current of $T_4$ and $T_5$