In electronics, a **voltage divider** or **resistor divider** is a design technique used to create a voltage (V_{out}) which is proportional to another voltage (V_{in}). ## Resistor divider
Two resistors are connected as shown in Figure 1. The output voltage, V_{out} is related to V_{in} as follows: As a simple example, if R_{1} = R_{2} then Any other ratio between 0 and 1 is also possible. Note that this rule only works if the divider is unloaded, that is, the load resistance is infinite and all of the current flowing through R_{1} goes into R_{2}. If current flows into a load resistance (through V_{out}), that resistance must be considered in *parallel* with R_{2} (see: resistor) to determine the voltage at V_{out}.
**Figure 1: Resistor Divider**
## General impedance divider A voltage divider is usually thought of as two resistors, but capacitors, inductors, or any combined impedance can be used. For general impedances Z_{1} and Z_{2}, the voltage becomes For instance, a divider with a resistor and capacitor:
will have voltage ratio:
since the capacitor's impedance is 1 / *jωC* (where *j* is the imaginary number, and *ω* is frequency in radians per second). The ratio then depends on frequency, in this case decreasing as frequency increases. This circuit is, in fact, a basic lowpass filter, or, in the world of audio, a treble-cut filter.
## See also ## External links - Calculator: voltage divider - loaded and open circuit (
*http://www.sengpielaudio.com/calculator-voltagedivider.htm*) |