Circuit/Current/Resistance Problem

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To find the current in a series circuit with three resistors, the total voltage across the resistors must be calculated. Given a supply voltage (Vs) of 12V, with voltage drops of 7V across R2 and 2.5V across R3, the voltage across R1 can be determined by subtracting these drops from Vs. This results in a voltage of 2.5V across R1, which is 220 ohms. Using Ohm's Law (I = V/R), the current can then be calculated, confirming the solution works effectively.
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I need help finding the current in a series circuit with 3 resistors! I have Vs = 12V, R1 = 220ohms, at R2 has a voltage drop = 7V, and at R3 has a voltage drop = 2.5V. How do I find the current? I Know I have to add up all the resistors but how do I find the other 2 unknown resistors?
 
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blackout77 said:
I need help finding the current in a series circuit with 3 resistors! I have Vs = 12V, R1 = 220ohms, at R2 has a voltage drop = 7V, and at R3 has a voltage drop = 2.5V. How do I find the current? I Know I have to add up all the resistors but how do I find the other 2 unknown resistors?

Welcome to the PF.

Think of those two resistive voltage drops just as voltage sources for a moment. What is the net voltage that is across the 220 Ohm resistor then? Does that help you to find the series current that is flowing around the whole circuit?
 
Holy! You are brilliant. I test it and it works! I will keep this in my note. Thank you Berkeman!
 
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