# How Do You Calculate Voltage Drops in a Simple Circuit?

• dasblack
In summary: You can use Ohm's law to find the voltage drop. For this problem, just remember that the voltage drop is the voltage divided by the resistance. So for instance, if there is a voltage drop of 6 volts across a wire with a resistance of 1 ohm, the voltage drop would be 6/1=6 volts. So in this case, the voltage drop across the light bulb would be 6 volts.
dasblack

## Homework Statement

Assume the wire resistance is 1.0 Ohms, the power supply is an ideal 6V voltage source, and the light bulb resistance is 30 Ohms.
In the circuit below:
a). A lightbulb is connected to the power supply using two such wires. Calculate the current (in A) in the circuit.
b) Calculate the voltage drop (in V) across each wire.

V=IR
R=dL/A

## The Attempt at a Solution

a.) I = 6/1 = 6ohms
b.) V = 6 x 1 = 6V

I have no clue how to do this problem. Professor hasn't taught this material yet.

Thanks

If the light bulb is connected with the two wires. Then the resistances are in series.
Find the total resistance. The total pd=6V.
So the total current is simply I=V/R.

The sum of the voltage drops across the wires and bulb will add up to be 6. So just use V=IR and you'll get it.

Consider this circuit as an ideal voltage source connected in series with 3 resistances (wire segment, light bulb, wire segment). Maybe redrawing the circuit will help. Ask yourself what the total resistance of the circuit is, and how this relates to the current. Then ask yourself how this current relates to the voltage drops across each individual element.

So for a.) I = 6/32 => 0.19 Amps

b.)V = 0.19 x 32 => 6 volts ?

a) is correct. For b) think of the individual wire elements. From the picture, it looks like each wire would have a resistance of 0.5 ohms. 6 volts is the drop in potential across the total resistance.

mplayer said:
a) is correct. For b) think of the individual wire elements. From the picture, it looks like each wire would have a resistance of 0.5 ohms. 6 volts is the drop in potential across the total resistance.

I see what you meant by the total resistance. Shouldn't each wire have a resistance of 1 ohm and not 0.5? From part a 2 ohms for the wires and 30 for the bulb

dasblack said:
I see what you meant by the total resistance. Shouldn't each wire have a resistance of 1 ohm and not 0.5? From part a 2 ohms for the wires and 30 for the bulb

Yes, you're right, each piece of wire is 1 ohm. I thought it was referring to the wire as a whole, and wanted you to divide the total wire resistance by 2 in order to split it up. Sorry for the confusion :/

Now for part b) you need to find the voltage drop across each piece of wire. You have the current through each piece, and you know the resistance of each piece.

## 1. What is a voltage drop in a circuit?

A voltage drop is a decrease in electrical potential energy that occurs when current flows through a circuit. It is caused by the resistance of the circuit components and can be measured in volts.

## 2. Why do voltage drops occur in circuits?

Voltage drops occur in circuits due to the resistance of the circuit components. As current flows through a circuit, it encounters resistance from materials such as wires, resistors, and other components. This resistance causes a decrease in voltage, which is known as a voltage drop.

## 3. How do you calculate voltage drops in a circuit?

To calculate the voltage drop in a circuit, you can use Ohm's Law, which states that voltage drop is equal to the current multiplied by the resistance. You can also use Kirchhoff's Voltage Law to calculate voltage drops in more complex circuits.

## 4. What can cause excessive voltage drops in a circuit?

Excessive voltage drops in a circuit can be caused by factors such as high resistance in the circuit components, inadequate wire size, or poor connections. Overloading the circuit with too much current can also lead to excessive voltage drops.

## 5. How can voltage drops be reduced in a circuit?

To reduce voltage drops in a circuit, you can use components with lower resistance, such as thicker wires and high-quality connections. Choosing the appropriate wire size for the circuit and avoiding overloading can also help reduce voltage drops. Proper maintenance and repairs can also prevent excessive voltage drops in a circuit.

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