# Difference between revisions of "electrical equations"

From Noah.org

m (Created page with 'Category:Engineering P = E^2 / R = Voltage Divider = == Voltage Divider No Load == Vout = Vin * (R2 / (R2 + R2)) Vin = Vout * ((R1+R2)/R2) <pre> Vout+ O Vout- O …') |
m (→Voltage Divider Under Load) |
||

(3 intermediate revisions by the same user not shown) | |||

Line 7: | Line 7: | ||

== Voltage Divider No Load == | == Voltage Divider No Load == | ||

− | Vout = Vin * (R2 / ( | + | The voltages are proportional to the resistances. |

+ | |||

+ | <pre> | ||

+ | Vout = Vin * (R2 / (R1 + R2)) | ||

Vin = Vout * ((R1+R2)/R2) | Vin = Vout * ((R1+R2)/R2) | ||

+ | </pre> | ||

<pre> | <pre> | ||

Line 22: | Line 26: | ||

== Voltage Divider Under Load == | == Voltage Divider Under Load == | ||

+ | |||

+ | <pre> | ||

+ | R2 || Rload = (R2 * Rload) / (R2 + Rload) | ||

+ | |||

+ | Vout = V1 * ( R2 ||Rload) / (R1 + R2 || Rload) | ||

+ | </pre> | ||

<pre> | <pre> |

## Latest revision as of 07:23, 20 January 2014

P = E^2 / R

## Contents

# Voltage Divider

## Voltage Divider No Load

The voltages are proportional to the resistances.

Vout = Vin * (R2 / (R1 + R2)) Vin = Vout * ((R1+R2)/R2)

Vout+ O Vout- O | | | | R1 | R2 | +--/\/\/--+--/\/\/--+ | | | | Vin+ Vin-

## Voltage Divider Under Load

R2 || Rload = (R2 * Rload) / (R2 + Rload) Vout = V1 * ( R2 ||Rload) / (R1 + R2 || Rload)

Rload +--/\/\/--+ | | | | Vout+ O Vout- O | | | | R1 | R2 | +--/\/\/--+--/\/\/--+ | | | | Vin+ Vin-

Vout = Vin (

## Picking a value for R1 and R2

Assume you have a restive sensor to test. Out of circuit you would test the sensor to determine its minimum resistance and maximum resistance. Then pick

R2 = sqrt (Rmin * Rmax)