Simple formulas give how voltage or current splits among resistors.
Voltage divider: V_out=V_in·R₂/(R₁+R₂). Current divider for two parallel resistors: I₁=I·R₂/(R₁+R₂). They scale signals and bias circuits. Loading by the next stage changes the ratio.
10 V across 1 kΩ and 4 kΩ gives 8 V across the 4 kΩ.
Dividers let you get a fraction of a voltage or current without a new supply, which is common in sensors and biasing networks.
Simple formulas give how voltage or current splits among resistors.
Dividers let you get a fraction of a voltage or current without a new supply, which is common in sensors and biasing networks.
Only when the divider is unloaded or when the load resistance is much larger than the divider resistors, otherwise the load changes the output.
Use the current divider rule, where each branch current is the total current times the other branch resistance divided by the sum of both.
Typical applications include setting a reference voltage from two resistors for an ADC input, splitting a supply to bias a transistor base and estimating the current sharing between two parallel heater elements.
Study "Kirchhoff's voltage law" first (topic 11 of 106 in Electrical Engineering). It covers the groundwork this topic builds on.
Quick mental calculations. Sensors use dividers. Keep load impedance high.
10 V across 1 kΩ and 4 kΩ gives 8 V across the 4 kΩ.
The next topic is "Resistor colour code and tolerance", which builds directly on this one.
It is classed as Beginner in Electrical Engineering (topic 12 of 106). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.