Resistor Voltage Drop Calculator: Series and Voltage Divider

How to Calculate Voltage Drop Across a Resistor

This calculator tool used to find out the two type of parameters which are,

• Ohms Law Drop (voltage drop or ohmic drop): A single connected or electrical component or resistor voltage drop and wattage is calculated.
• Voltage Divider: In two resistor connected divider circuit step down voltage is measured. The resistor R1 connect to positive and R2 to the negative.

The Mathematics Behind Resistor Voltage Drops

Understands how the voltage drop is occurs by using the standard mathematical formulas. For single resistor based voltage drop and voltage divider circuit has different equations which are given below,

1. Single Resistor Drop via Ohm's Law

The current passing through the resistor the voltage drops. This can be calculated using the ohms law of,

V_drop = I x R

• Where the V_drop representing the Voltage drop, I represents the current in Ampere and R is resistance in ohms.
• Example: An LED is connected in series using a 470 ohms Resistor the current across the LED is about 20mA (0.02A) the voltage drop across the resistor is 0.02 x 470 = 9.4V.

To Protect the Connected LED we also using joules law top find out the power using equation of ,

P = I² x R

2. Series Voltage Divider Calculation

The voltage divider reduces the input voltage to lower output voltage. This happens due to the arrangement of two resistors connected one in positive side and other one to the negative. The output voltage V_out is calculated using the given formula of,

V_out = V_in x R2 / R1+R2

Real World Applications of Voltage Dividers

• Used as a reference voltage for Arduino and other microcontroller IC.
• Step down the 5V power from safest 3.3V for Microcontroller IC.
• The rotational potentiometer is using the same method of configuration inside.

Frequently Asked Questions

Related Tools: "Try our Free online Resistor Color Code Checker tool or our LED Series Resistor Calculator."