Identify the circuit configuration and make necessary assumptions.

Step 1: Identify the circuit configuration and make necessary assumptions.
The circuit shows a current mirror configuration. Transistor $Q_1$ is diode-connected (collector shorted to base), acting as a reference current generator. Transistors $Q_2$ and $Q_3$ are the output transistors, mirroring the current set by $Q_1$. All three transistors share a common base voltage and have their emitters grounded.

Assumptions:

• All transistors ($Q_1, Q_2, Q_3$) are identical NPN BJTs.
• They are operating in the active region.
• The base-emitter voltage ($V_{BE}$) for silicon BJTs is approximately $0.7 \text{ V}$.
• The current gain ($\beta$) for the