Ohm's Law - Finding Source Voltage

In summary, "Ohm's Law - Finding Source Voltage" explains how to determine the source voltage in an electrical circuit using the relationship defined by Ohm's Law (V = I × R), where V is the voltage, I is the current, and R is the resistance. The document outlines the steps to rearrange the formula to solve for source voltage when the current and resistance are known, emphasizing its practical applications in circuit analysis.
  • #1
Brian82784
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TL;DR Summary: Ohms Law Source Voltage DC series Circuit

Hello,

I'm trying to figure out how to determine source voltage of a DC series circuit. The only information given is

Resistor 1 = 12ohm
Resistor 2 = 9ohm
Resistor 3 = 3ohm

And the voltage drop across R1 is 6V.

The answer is 12V for the DC battery. But I can't figure out how to get to 12.

If I put 12V down as the battery size, and combine all three resistors 24ohm and use ohms law I can't come up with 12V.

R total = 24ohm
12V source battery

24 divided by 12 = 2Amps

Now if I go to R1 and knowing that the circuit amperage is 2, I get a voltage drop of 2A * 12ohm = 24V not 6V.

Where am I going wrong?
 
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  • #2
Brian82784 said:
24 divided by 12 = 2Amps
Reminder: V=IR :wink:
 
  • Like
Likes Gavran
  • #3
Brian82784 said:
And the voltage drop across R1 is 6V.
So this gives you the current through R1, and hence that same current flows through all 3 series resistors. :smile:
 
  • #4
Brian82784 said:
Resistor 1 = 12ohm

And the voltage drop across R1 is 6V.
So what is the current?
 

FAQ: Ohm's Law - Finding Source Voltage

What is Ohm's Law?

Ohm's Law is a fundamental principle in electrical engineering that states the relationship between voltage (V), current (I), and resistance (R) in an electrical circuit. The law is usually expressed with the formula V = I * R, where V is the voltage, I is the current, and R is the resistance.

How do you calculate the source voltage using Ohm's Law?

To calculate the source voltage using Ohm's Law, you need to know the current flowing through the circuit and the resistance of the circuit. The formula to find the source voltage (V) is V = I * R. Simply multiply the current (I) by the resistance (R) to find the voltage.

What units are used in Ohm's Law?

In Ohm's Law, the units used are volts (V) for voltage, amperes (A) for current, and ohms (Ω) for resistance. These units are standard in electrical engineering and help ensure consistency and accuracy in calculations.

Can Ohm's Law be applied to both AC and DC circuits?

Yes, Ohm's Law can be applied to both alternating current (AC) and direct current (DC) circuits. However, in AC circuits, the impedance (which includes resistance and reactance) must be considered instead of just resistance. For simple DC circuits, only resistance is considered.

What happens if the resistance in a circuit is zero?

If the resistance in a circuit is zero, according to Ohm's Law (V = I * R), the voltage (V) would also be zero if the current (I) is finite. This situation typically indicates a short circuit, which can cause a very high current flow and potentially damage the circuit components or create safety hazards.

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