Table of Contents

## How do you decide the value of a resistor?

To select a resistor for a specific application, the following steps are recommended:

- 1 . (a) Determine the Resistance.
- 2 . Determine the proper “Watt Size” (physical size) as controlled by.
- 3 .
- step 1 deteRmiNe ResistANce ANd wAtts.
- step 2 poweR RAtiNg oR physicAl size oF ResistoR.
- Ambient Temperature.
- Enclosure.
- Grouping.

**How do you determine the power rating of a resistor?**

A resistor’s power rating can usually be deduced by observing its package size. Standard through-hole resistors usually come with ¼W or ½W ratings. More special purpose, power resistors might actually list their power rating on the resistor. These power resistors can handle a lot more power before they blow.

### How is the value of a power resistor indicated?

Resistor values are usually shown using coloured bands, each colour represents a number as shown in the table. Most resistors have 4 bands: The first band gives the first digit. The fourth band shows the tolerance (precision) of the resistor but this may be ignored for almost all circuits.

**How do you find the value of a resistor in a series circuit?**

This is done by adding up the individual values of each component in series. In this example we have three resistors. To calculate the total resistance we use the formula: RT = R1 + R2 + R3.

#### How do you calculate the power rating?

Calculate power rating in KVA when you know voltage and output resistance. Use the formula: P(KVA) = (V^2/R)/1000 where R is resistance in ohms. For example, if V is 120 volts and R is 50 ohms, P(KVA) = V^2/R/1000 = (14400/50)/1000 = 288/1000 = 0.288 KVA.

**What is a power resistor?**

What Are Power Resistors? Power resistors are designed to withstand and dissipate large amounts of power. An example use for power resistors are load banks used to dissipate power generated during engine braking in vehicles using electrical motors, such as locomotives or trams.

## How do you know which way to read a resistor?

Always read resistors from left to right. – Resistors never start with a metallic band on the left. If you have a resistor with a gold or silver band on one end, you have a 5% or 10% tolerance resistor. Position the resistor with this band on the right side and again read your resistor from left to right.

**How to choose the right resistor for your circuit?**

How do I Choose the Right Resistor? 1 Step 1 – Calculating Your Resistance. This is where you will use Ohm’s Law to calculate your resistance. You can use one of the standard formulas 2 Step 2 – Calculating Your Power Rating. 3 Step 3 – Choosing a Resistor.

### What is the power rating of a resistor?

Standard resistors often have a power rating of 0.25W (Watt). If you look at a worst-case scenario, all the 9V of the voltage source would drop across the resistor. With a resistor of 324 Ω you’ll be at the limit of what the resistor can handle if there is a 9V drop over it.

**Why do you use lower value resistor in divider?**

The more current is flowing through these resistors, the less the input current will effect things. So any time you have a divider you are trying to balance accuracy vs. power consumption. Higher current (lower value resistors) will give you better accuracy at the cost of increased power consumption.

#### How is output voltage determined by resistor ratio?

I understand that the output voltage is determined by the ratio between the two resistor values, and that if the both resistors are same then output voltage will be exactly same for all; but what’s… Stack Exchange Network