Resistors in Parallel

Resistors in Parallel
Resistors in Parallel

Resistors in parallel have the same two nodes linked to the circuit and are connected side by side. This permits current to divide between resistors. By knowing resistors in parallel, one can explore their applications and benefits.

Parallel resistor generate an equivalent resistance by connecting resistors in parallel. All resistors’ positive terminals are linked to the same node, while their negative terminals are connected to another. It divides current and voltage across resistors.

So what are parallel resistor? In a parallel circuit, two or more resistors are directly linked to the voltage source. Knowing that each resistor in a parallel circuit has the same current is crucial. The circuit’s total resistance is smaller than any resistor’s.

Resistors in Parallel
Resistors in Parallel

Total Resistance Calculation

To calculate parallel resistor’ total resistance (RT), use this formula: 1/RT = R1+R2+R3… The resistances of each resistor are R1, R2, R3, etc. If two resistors of 10 Ω and 20 Ω are connected in parallel, the total resistance is: 1/RT = 1/10 + 1/20. 1/RT = 0.1 + 0.05 = 0.15 RT = 1/0.15 = 6.67 Ω


Each resistor in a parallel circuit has the same current (I), but its voltage (V) depends on its resistance. Low-resistance resistors drop voltage more. Sum of resistor currents equals circuit current.

2.1. Parallel total resistance formula

Parallel circuit total resistance is calculated using the formula: 1/Rt = 1/R1 + 1/R2 +…+ 1/Rn. This formula uses Rt for total resistance and R1, R2, Rn for parallel resistances. We calculate total resistance by summing the reciprocals of each resistor’s value. The resistances are combined into one resistance by this equation. Rt = (R1 * R2) / (R1 + R2) is a simplified formula for two parallel resistor.

2.2. Total resistance example

To demonstrate parallel total resistance computation, take an example. Consider two resistors, R1 and R2, with 3 and 5 ohms, respectively. We may determine total resistance using the formula above: 1/Rt = 1/3 + 1/5. Finding a common denominator and adding the fractions yields 1/Rt = 8/15 = (5 + 3) / (3 * 5). The reciprocal of both sides yields Rt = 15/8, or 1.875 ohms. The combination has 1.875 ohms of resistance.

Benefits of parallel resistor

Parallel resistor have many benefits. As the combined resistance decreases, the circuit’s current capacity increases. Second, it provides redundancy, allowing one resistor to work if another fails. Parallel resistor allow more precise and flexible current and voltage control in a circuit. This flexibility improves component regulation and protection.

Actual Uses

A parallel resistor is helpful for:

  • Resistance determines voltage across each resistor. To adjust voltage, use this.
  • Current sharing: Resistors share the current. This lets numerous resistors manage higher currents.
  • Electronic circuits: Parallel resistors manage voltage and current in amplifiers, power supply, and other circuits.
  • Learning how current, voltage, and resistance work in parallel resistor circuits will simplify their operation. A little practice will make parallel resistor network calculations easy.

Calculating Parallel Resistor Total Resistance

Parallel resistors reduce circuit resistance. To calculate parallel resistors’ total resistance (RT), use this formula:

1/RT = R1+R2+R3…

The resistors’ resistance values are R1, R2, and R3. If you parallel a 10 ohm, 20 ohm, and 30 ohm resistor, the overall resistance is:

1/RT = 1/10 + 1/20 + 1/30
1/RT = 0.1 + 0.05 + 0.033 = 0.183 RT = 5.46 ohms

Parallel circuit total resistance depends on several factors:

• Individual resistor resistance: Lower resistance values lower total resistance. Higher resistance values increase total resistance.

More parallel resistors lower resistance. Removing resistors raises resistance.

• Resistor tolerance: Resistors with 1% or 0.1% tolerance give more exact total resistance than 20% tolerance resistors.

Temperature: Rising temperature lowers resistance, lowering total resistance. A drop in temperature increases resistor resistance, increasing overall resistance.

Using parallel resistors creates voltage dividers and shares current between circuit elements. Lower resistance means bigger voltage drop across each resistor. Current flow is inversely proportional to resistor resistance. Amplifiers and filters use parallel resistors to adjust voltage and current.

Understanding how to compute total resistance for parallel resistors simplifies this handy circuit layout. You can wire parallel resistors quickly with some simple arithmetic and an eye on overall resistance factors!

Understanding Parallel Circuit Current and Voltage

Resistance in parallel affects current and voltage differently than in series. With parallel resistors, the current is the same but the voltage lowered varies on resistance.

In a parallel resistor circuit, I equals the sum of the currents across each resistor. If two resistors have currents I1 and I2, their total current is I = I1 + I2. Parallel branches divide the current, with more flowing along lower-resistance routes.

If R1 = 10 ohms and R2 = 50, I1 = 5 amps and I2 = 1 amp. Thus, I = 5 amps plus 1 amp = 6 amps.

The voltage (V) dropped across each resistor relies on its resistance (R) following Ohm’s rule (V = IR). V1 = I x R1 = 6 amps x 10 ohms = 60 volts across R1. V2 = I x R2 = 6 amps x 50 ohms = 300 volts across R2. Even if currents are the same, higher resistance pathways have higher voltages.

This means bigger voltages drop over higher resistance parallel resistors with unequal voltage distribution.

Understanding parallel resistor circuit current and voltage will help you understand more sophisticated parallel circuits. Remember that parallel branches have the same current, but voltages depend on resistances. You’ll decipher parallel resistor circuits quickly with this knowledge!

Real-World Parallel Resistor Circuit Applications

Parallel resistor circuits have several popular real-world applications.

Dividers voltage

Voltage dividers split input voltages into two lower voltages using parallel resistors. The voltage division ratio depends on resistor values. Circuits often use voltage dividers to establish reference voltages.

Currently Sharing

Parallel resistors share circuit current. The current through each resistor is proportional to its resistance. In high-power applications where no resistor can manage all the current, current sharing is crucial.


If one resistor fails open, parallel resistor provide redundancy. As long as one resistor works, overall resistance remains stable. Resistance-critical applications like voltage dividers benefit from this. System operation can continue if one resistor fails open until it is replaced.

Parallel resistor circuits can create voltage dividers, share current loads, and provide electronic circuit redundancy. They let you choose resistance values. You’ll understand parallel resistors in circuit diagrams now.


You now understand parallel resistors and their use in electronic circuits. The formula for total resistance and examples of current flow across parallel resistors allow you to create simple circuits for voltage division or current handling capability. Your following diagram with parallel resistors will explain how those components work. Parallel resistors aren’t so weird!

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