Series voltage divider
The current is the same, so how is the voltage shared?
In a series circuit the current is the same everywhere, and the total voltage equals the sum of the voltages across the resistors. The larger a resistance, the larger its share of the voltage; changing either resistor changes the current throughout the circuit.
Voltage shares vs. source voltage
When the two resistances are equal, the voltage curves coincide.
Think about it
If R₂ is doubled, does the voltage across R₁ increase too?
No. With the total voltage fixed, the larger total resistance reduces the current, so the voltage across R₁, U₁ = IR₁, actually decreases; the share across R₂ increases.
Model assumptionsIdeal DC source and ohmic resistors · No wire resistance · Dots show the conventional current direction; their speed only indicates the current size
Data log
Set the parameters and click “Record data”. Record several rows with different parameters to plot their relationship and fit a straight line; pause and record at different times to study how a reading changes with time.