Final answer:
To construct the Thévenin equivalent circuit, combine resistors in series and parallel, then apply Ohm's law to find equivalent resistance and voltage, modeling the network external to resistor R.
Step-by-step explanation:
To find the Thévenin equivalent circuit for the network external to the resistor R, we must determine the equivalent resistance and voltage. The details provided suggest a process involving combining resistors in series and parallel configurations. Specifically, resistors R₂ and R₃ are combined in parallel to find their equivalent resistance, Rp, which is then combined in series with R₁. Following the combination of resistors into single equivalent resistances, we apply Ohm's law to determine the equivalent voltage for the Thévenin circuit. By simplifying the network into a single equivalent resistance and a single voltage, we can model the network external to the resistor R.