Voltage Divider

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A two-resistor voltage divider — the smallest circuit in the library and a good first run.

Voltage divider: a 10 V DC source across two equal 1 kΩ resistors in series. The tap between them is $V_{\mathrm{mid}}$.

A DC source drives two resistors in series, and the node between them sits at a fraction of the input set purely by the resistor ratio (Vout = Vin · R2 / (R1 + R2)). Open it, press Run, and watch the divided output settle on the plot — then change a resistor value and run again to see the output move.

With two equal 1 kΩ resistors, V_mid sits at exactly half the 10 V input — a flat 5 V line. There is no capacitor or inductor to store energy, so nothing evolves in time: the divider is in its final state from the very first step (here a 50 µs step over a 0.2 s window). This is the ideal first circuit — it isolates Kirchhoff's laws with no transient to distract you. Try making R2 nine times R1 and the tap drops to 1 V; short R2 and it collapses to 0 V.