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Shunt
,==How does a shunt works?==
'''Short:'''<br>
A shunt is a very small resistor that is used to measure current.
The resistor is added in series to the load and the voltage drop is measured.
'''In Detail:'''<br>The best way to get a better understanding is to have a look at the principle of voltage divider.<br>[[Datei:Voltage-divider-shunt.png]]<br>In a voltage divider the current is always the same.<br>[[Datei:I_total.gif]]<br>
-> Means we can really use a second resistor to find out the current that is flowing through the load.
Every resistor has a voltage drop that has the ratio of the resistor to the total resistance.<br>[[Datei:r_total_shunt.gif]]<br>[[Datei:ratio_r_shunt.gif]]<br>[[Datei:v_drop_shunt.gif]]<br>-> This tells us that we have to choose the resistor as small as possible so that we don’t drag to much voltage from the load.
{| class="wikitable"
|-
! I (total)
! U (total)
! R_load
! R_shunt
! U (load)
! U (shunt)
! P (lost)
|-
| 0,25A
| 5V
| 10
| 10
| 2.5V
| 2.5V
| 0.625W
|-
| 0,25A
| 5V
| 19
| 1
| 4.75V
| 0.25V
| 0.0625W
|-
| 0,25A
| 5V
| 19.9
| 0.1
| 4.975V
| 0.025V
| 0.00625W
|}