As can be seen from the name voltage divider, it is an electronic circuit with which the voltage is divided. It is a passive circuit consisting of a series connection of two or more resistors through which the same current flows.
Due to the division ratio of the resistors, the voltage drops across the resistors correspond to the ratio of the resistance values of the voltage divider.
For a simple, unloaded voltage divider consisting of two resistors, the voltage is divided in the ratio of the resistor values. If one resistor R1 has the value 1 and the second resistor R2 has twice the resistance value 2, then the voltage U is divided in the ratio 1:2. For example, if the applied voltage is 6 V, then the voltage value U2 between the resistor values is 4 V.
The classic passive voltage divider is relatively inefficient because current is constantly flowing through the voltage divider. This current flow can be reduced by increasing the resistor values, but this has the disadvantage that the output resistance of the circuit increases and is loaded by the internal resistance of the subsequent circuit. Ideally, the voltage divider should have an output resistance of zero as a voltage source.