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This circuit illustrates the working principle of a voltage divider bridge.
The input voltage (denoted U_in) and the value of the "big" resistor (i.e. the potentiometer, denoted R_big) are set to 1V and 1Ω respectively to make the experience easier to understand.
The potentiometer can be seen as two resistors wired up in series, which we'll denote as R_up and R_down. R_up is measured across the two upper leads, and so is R_down across the two lower leads of the potentiometer. R_big is measured across the upper and the lower leads and we have the following relation :
▪︎ R_big = R_up + R_down
Adjusting the "Wiper position" parameter of R_big will change the value of both R_up and R_down, without changing the value of R_big. This parameter is set to 70% by default, which means that R_up = 70% of R_big and so R_down = (100 - 70)% of R_big.
The blue, green, and orange voltmeters are wired up to probe respectively the voltage across R_big, R_up, and R_down, which we'll denote as U_big, U_up, and U_down.
Let finally denote I_big, I_up, and I_down the currents flowing through R_big, R_up, and R_down.
We end up with the following relations :
▪︎ U_up = U_dig × R_up / R_big
▪︎ U_down = U_big × R_down / R_big
Feel free to play around with the value of the "Wiper position" and all the other parameters to observe the effects on the different voltages.
Enjoy ^_^
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