**Voltage divider calculator** calculates the voltage drops on each resistor load, when connected in series. Enter total voltage supply and press the *Calculate* button:

## Voltage divider rules

### Voltage divider rule for DC circuit

For a DC circuit with constant voltage source **V _{T}** and resistors in series, the voltage drop

**V**in resistor

_{i}**R**

_{i}is given by the formula:

*Where:*

*V*_{i} – voltage drop in resistor R_{i} in volts [V]* V_{T}* – the equivalent voltage source or voltage drop in volts [V]

**R**_{i}– resistance of resistor

*R*

_{i}in ohms [Ω]

**R**_{1}– resistance of resistor

*R*

_{1}in ohms [Ω]

**R****– resistance of resistor**

_{2}*R*

_{2}in ohms [Ω]

**R****– resistance of resistor**

_{3}*R*

_{3}in ohms [Ω]

#### Example

Voltage source of** V _{T}=30V** is connected to resistors in series, R

_{1}=30Ω, R

_{2}=40Ω. Find the voltage drop on resistor

**R**

_{2}.

*V*_{2} = *V*_{T} × *R*_{2 }/ (*R*_{1}+*R*_{2}) = 30V × 40Ω / (30Ω+40Ω) = 17.14V

### Voltage divider for AC circuit

For an AC circuit with voltage source V_{T} and loads in series, the voltage drop V_{i} in load Z_{i} is given by the formula:

*V*_{i} – voltage drop in load Z_{i} in volts [V].

*V _{T}* – the equivalent voltage source or voltage drop in volts [V].

*Z*

_{i}– impedance of load

*Z*

_{i}in ohms [O].

*Z*

_{1}– impedance of load

*Z*

_{1}in ohms [O].

*Z*

_{2}– impedance of load

*Z*

_{2}in ohms [O].

*Z*

_{3}– impedance of load

*Z*

_{3}in ohms [O].

#### Example

Voltage source of VT=30V∟60° is connected to loads in series, Z1=30Ω∟20°, Z2=40Ω∟-50°.

**Find the voltage drop in load Z _{1}**

*V*_{2} = *V*_{T} × *Z*_{1 }/ (*Z*_{1}+*Z*_{2})

= 30V∟60° × 30Ω∟20° / (30Ω∟20°+40Ω∟-50°)

= 30V∟60° × 30Ω∟20° / (30cos(20)+j30sin(20)+40cos(-50)+j40sin(-50))

= 30V∟60° × 30Ω∟20° / (28.19+j10.26+25.71-j30.64)

= 30V∟60° × 30Ω∟20° / (53.9-j20.38)

= 30V∟60° × 30Ω∟20° / 57.62Ω∟-20.71°

= (30V×30Ω/57.62Ω) ∟ (60°+20°+20.71°)

= 15.62V∟100.71°

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Dan

Why do you need a software? Pretty easy to calculate on paper.

Also, very easy to program in a software too.

dileep kumar gupta

please provide the software.

fabio

@Dileep, how many things did you provide for free ? How much work for the community did you do? Coz I see you’re quick at asking for some more of other’s