Series Resistor Calculator
Calculate equivalent resistance of resistors connected in series
Calculate Series Resistance
Series Resistance Results
Formula: Rtotal = R₁ + R₂ + R₃ + ... + Rn
Calculation: = 0.000Ω
Note: In series circuits, current is the same through all resistors, but voltage divides proportionally
Circuit Analysis
Example Calculation
LED Current Limiting Circuit
Circuit: 9V battery → 470Ω resistor → 220Ω resistor → LED
Resistor 1: 470Ω (current limiting)
Resistor 2: 220Ω (additional current limiting)
LED forward voltage: ~2V
Calculation
Rtotal = R₁ + R₂ = 470Ω + 220Ω = 690Ω
Voltage across resistors = 9V - 2V = 7V
Current = V/R = 7V/690Ω = 10.14 mA
Safe current for standard LED operation
Series vs Parallel
Series Resistors
Rtotal = R₁ + R₂ + R₃...
Total resistance increases
Parallel Resistors
1/Rtotal = 1/R₁ + 1/R₂ + 1/R₃...
Total resistance decreases
Key Differences
- • Series: Same current, different voltages
- • Parallel: Same voltage, different currents
- • Series: Higher total resistance
- • Parallel: Lower total resistance
Common Resistor Values
Series Circuit Tips
Current is the same through all resistors
Total voltage equals sum of individual voltages
One open circuit stops current flow everywhere
Used for voltage division and current limiting
Higher resistance = lower current
Understanding Series Resistor Circuits
What are Series Resistors?
Series resistors are connected end-to-end in a single path, so the current flows through each resistor sequentially. The total resistance is simply the sum of all individual resistances, making series circuits useful for current limiting and voltage division.
Key Characteristics
- •Current is identical through all components
- •Voltage divides proportionally to resistance
- •Total resistance always increases
- •One failed component breaks the entire circuit
Series Resistance Formula
Rtotal = R₁ + R₂ + R₃ + ... + Rn
Sum of all individual resistances
Current and Voltage
I = Vsupply / Rtotal
Vresistor = I × Rresistor
Ohm's Law applications
Practical Tip: Use series resistors for LED current limiting, voltage dividers, and pull-up/pull-down circuits in digital electronics.
Common Applications
Current Limiting
Protect LEDs and sensitive components from excessive current
Voltage Division
Create specific voltage levels for sensors and reference circuits
Pull-up/Pull-down
Ensure defined logic levels in digital circuits