To solve the problem, let's analyze the circuits and calculate the overall current gain for each.

Understanding the problem:

• Q1 (npn) has a current gain ($\beta_1$) of 100.
• Q2 (pnp) has a current gain ($\beta_2$) of 50.
• The overall current gain for a two-transistor Darlington or similar compound configuration can be approximated by: $\beta_{\text{overall}} = \beta_1 \cdot \beta_2 + \beta_1 + \beta_2$ However, for high values of $\beta_1$ and $\beta_2$, the term $\beta_1 \cdot \beta_2$ dominates, so it simplifies to: $\beta_{\text{overall}} \approx \beta_1 \cdot \beta_2$

Calculations for the two circuits:

1. For the first circuit (left side):

   • Current gain of Q1 ($\beta_1$) = 100
   • Current gain of Q2 ($\beta_2$) = 50 $\beta_{\text{overall}} = 100 \cdot 50 = 5000$

2. For the second circuit (right side):

   • The configuration and calculation method remain the same.
   • $\beta_{\text{overall}} = 5000$

Answer:

The overall gain for each circuit is 5000.

Let me know if you'd like further clarifications or additional details! Here are five related questions to deepen your understanding:

1. How would the overall gain change if $\beta_1$ or $\beta_2$ increased or decreased?
2. What are the advantages of using such compound transistor configurations?
3. How does this calculation change for circuits with additional resistors or feedback loops?
4. Can this calculation apply to circuits with three or more transistors?
5. What practical applications benefit from high current gain in transistor circuits?

Tip: Always check the operating conditions (like saturation and cutoff regions) to ensure the calculated gains are achievable in real circuits!