Why are some resistors so much larger physically than others?

The larger the size of resistor the more surface area there is to dissipate heat to the air and also more volume to absorb heat. Another method to dissipate heat is to mount the resistor on a thermal conductive material which further increases the surface area exposed to air.

Does the physical size of a resistor matter?

Generally speaking the larger their physical size the higher its wattage rating. However, it is always better to select a particular size resistor that is capable of dissipating two or more times the calculated power.

Why might resistor values differ from nominal values?

Resistors have a nominal value indicated by colored bands or other labeling. The actual (measured) resistance will vary from the nominal value due to subtle mechanical and chemical differences that occur during manufacturing. The manufacturer specifies the maximum deviation from the nominal value as a ±percentage.

When a resistor increases its physical size which one will increase power or resistance?

Generally, larger the resistor more power it can handle. As the wattage of the resistor increases cost also increases. Resistors generally start from 1/8th watt to many kilo watts. Resistor wattage can be noticed by seeing the size of the resistor.

Why are resistors needed?

Resistors ensure components receive the proper voltage by creating a voltage drop, and they can protect a component from voltage spikes. If a component in your circuit requires less voltage than the rest of your circuit, a resistor will create a voltage drop to ensure the component does not receive too much voltage.

What determines the size of a resistor?

The physical size of the resistor is directly related to how much wattage it can accomodate. The larger the resistor the more wattage, or the more power it can dissipate. The amount of heat dissipated per unit time is measured in watts.

How accurate is the value of a resistor as provided by the manufacturer?

The manufacturer specifies the maximum deviation from the nominal value as a ±percentage. This range of deviation is called the tolerance of the resistor family. Typical tolerance values are ±1\%, ±5\%, or ±10\%.

How do you compare the computed value of resistance to the resistance of the resistor?

If your resistors are placed in series, then the equivalent resistance that is seen by the circuit is the sum of your resistor values. On the other hand, if your resistors are placed in parallel, then your equivalent resistance is found by adding the inverses of your resistor values.

Is there a direct correlation between the physical size of a resistor and its resistance value?

Resistor resistance ratings cannot be determined from the physical size of the resistor(s) in question, although approximate power ratings can. The larger the resistor is, the more power it can safely dissipate without suffering damage.

How will resistance change if we duplicate both the length and the cross sectional area of a resistor?

If you double both length and cross-sectional area of a wire, you will (double / triple / quadruple) the resistance of the wire. 2. To cut the resistance of a wire in half, you may (cut the resistivity in half / double the length / quadruple the area).

Why do resistors come in different sizes?

Resistors come in different sizes depending on how much power they can safely dissipate. Larger packages dissipate higher wattage. No matter what the size, the color code is the same. For non-cylindrical and some large cylindrical resistors, the resistance is indicated with letters and numbers printed on the package.

Do all resistors have the same power rating?

However it is also common to see metal film resistors with the same power rating as carbon film resistors of the same body size. Resistors come in different sizes depending on how much power they can safely dissipate. Larger packages dissipate higher wattage. No matter what the size, the color code is the same.

How to determine the resistance of a non-cylindrical resistor?

For non-cylindrical and some large cylindrical resistors, the resistance is indicated with letters and numbers printed on the package. What you have in your picture look like 1/2 W and 1/4 W resistors. Yes, the resistance is similar, the color code only decides what the resistance is (plus/minus some accuracy, also color coded).

What is the resistance of a resistor with 10 volts?

For the circuit conditions of 10 volts and 2 amps, the resistor’s resistance must be 5 Ω. If we were designing a circuit to operate at these values, we would have to specify a resistor with a minimum power rating of 20 watts, or else it would overheat and fail.