Calculating voltage across resistors

In summary: I(R2):grumpy: 3V = IRY - 0 = I(R4):grumpy: 4V = IRZ - Y = I(R3)In summary, the conversation is discussing a problem involving calculating the voltage at a specific point in a circuit. The first scenario involves a voltage divider equation, while the second and third scenarios require using Ohm's law to find the voltage at different points in the circuit. The solution involves finding the electric current and then using Ohm's law to calculate the voltage at each point.
  • #1
ingram010
14
0
Hi all,

I am looking for a formula to work out the following-


500v---/\/\/\/\/---X---/\/\/\/\/---0v
1megohm 10kohm

what is X?

cheers
 
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  • #2
Welcome to PF. Its not clear at least to me what the problem is, is X an unknown voltage. If so
use V=iR first compute i using the total series resistance (here the sum of 1Mohm and 10Kohm.
Then V is just the i*the resistance over which you want to find voltage.

or all in one v=500*R/(R+r) This is just voltage divider eqn. Thats the voltage across the first resistance, voltage across the second would be:

500*r/(R+r), if your looking for the value of x, this would be the one to use.
 
Last edited:
  • #3
voltage calculation

Hi, on reflection it isn't very clear. Sorry.


how about this-

500v---\/\R1\/\----X----\/\R2\/\---0v

If R1 = 1Mohm and R2 = 10Kohm
what is the voltage at X?

Or this one -

500v---\/\R1\/\--X--\/\R2\/\--Y--\/\R3\/\--Z--\/\R4\/\---0v

If R1 = 1Mohm, R2 = 10Kohm, R3 = 10Kohm and R4 = 10Kohm
what is the voltage at X,Y and Z?

is there a simple calculation for this problem?
 
  • #4
first find the electric current
then use Ohm's law
V=IR
500=I(106+103)
I = ?
1
V = IR
X - 0 = I(R2)

2
V = IR
500 - X = I(R1)
 

Related to Calculating voltage across resistors

1. How do you calculate the voltage across a resistor?

The voltage across a resistor can be calculated using Ohm's Law, which states that voltage (V) is equal to the product of current (I) and resistance (R). This can be expressed as V = IR.

2. What units are used to measure voltage?

Voltage is measured in volts (V), which is a unit of electrical potential difference.

3. Can the voltage across a resistor change?

Yes, the voltage across a resistor can vary depending on the amount of current flowing through it. As the current increases, the voltage across the resistor will also increase.

4. How does the value of the resistor affect the voltage across it?

The higher the resistance of a resistor, the lower the voltage across it will be for a given current. This is because the resistor restricts the flow of electrons, causing a voltage drop.

5. Can you use Ohm's Law to calculate voltage for multiple resistors in a circuit?

Yes, Ohm's Law can be applied to calculate the voltage across multiple resistors in a series circuit. The total voltage will be equal to the sum of the individual voltage drops across each resistor.

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