Q&A for How to Calculate Voltage Across a Resistor

It would be 35%. The higher the resistance, the higher the voltage drop. The ratio of resistances here is 80:50:70. Solving for 70 ohms, we get 35%.

Assuming you intend to ask what is the voltage drop across the 60 ohm resistor, the answer is 120v. The two parallel 30 ohm resistors have an equivalent resistance of 15 ohms. 1/(1/30 + 1/30) = 15. The total resistance appears as 75 ohms to the 150v source. Find the circuit current by I = E/R or I = 150/75 = 2 amps. Find the voltage drop for the 60 ohm resistor with E = I x R or E = 2 x 60 = 120V drop across the 60 Ohm resistor.

As any other data is not provided, the voltage across two resistors of 4w in parallel is the same.

The current in any part of a series circuit is the same everywhere.

You calculate the voltage drop over a component in a circuit by finding the current and resistance running through and exerted upon the component before multiplying them together.

You know the resistance and the current (which is the same anywhere in a series circuit). The voltage drop for each resistor is E(x) = I x R(x) for each resistor (x), i.e., R(1), R(2), R(3).

You take the basic formula of E = I x R, solve for R -> R = E / I. In other words, take the required voltage drop (in volts) and divide by the current (in amps) in the resistor and determine the resistance (R) in ohms.

You find the resistance of the series portion by adding together the resistances. You then find the resistance of the parallel portions with the formula shown above: 1 / Rtotal = 1 / R1 + 1 / R2 + 1 / R3... If the series resistances are in series with the parallel, you add them together with the calculated parallel resistance. If the series resistances are in parallel with others, they become one of the resistances, "R1", of the parallel formula for calculating their contribution to the resistance of the entire circuit.

The voltage drop is already known, if all you have is a resistance and a known voltage. The current can be determined by dividing the voltage by the resistance, if that's what you're asking.

The voltage of the combination of multiple cells (batteries) in series is the sum of the voltage of all the cells. Two 9-volt batteries in series would give you 18 volts.

Given a required voltage drop, you would need to know the current and then use E = I x R rearranged to solve for the necessary value of R, or R = E/I, the voltage drop divided by the current through that resistance.

To calculate the voltage drop across a resistor, remember: Ohm's Law (V=I*R) is your friend. Find the current flowing through a resistor, then multiply the current in amps by resistance in ohms to find the voltage drop in volts.

The capacitance in a parallel circuit of capacitors is the sum of the individual capacitances.

This results from the fact that there is an open in the circuit. Some would say that this means infinite resistance: the resistance is so high that the current is effectively zero amps.

The voltage drop across a resistance is determined by the current (amps, I) multiplied by the resistance (ohms, R), as denoted in the formula: E = I x R.