Good day steemians!

For today’s tutorial, I will show to you how to read the value of a resistor. If you noticed from my previous tutorials, most of my contents are related to circuits, electronics, and engineering. Yes. I am choosing these topics because these are my passions. For some individual, they may find this one as easy or they already know it. I admit it. This tutorial is a basic. But, my intention for this is not to educate the educated one’s. Sharing my works, my knowledge makes me grow. What am trying to do is to give information to people who are not into it. Some say or most say that engineering things are complicated, complex and very difficult. Well, we can make it simpler to them by educating them start from the basics. Basics from a strange thing will always be appreciated. I hope you will appreciate it and be useful to you.

Limitation of this tutorial.

This tutorial is limited only to 4 bands carbon composition resistor. I am using carbon resistor because it was a part of my tutorial to compare using color coding scheme and using analog multimeter. Carbon resistor uses color code in its packaging and not all resistor type uses color coding. Resistor color coding comes in 3, 4, 5, and 6 bands of color. I am using 4 bands it is the most common one.

Source

Color Coding Chart.

Source

Let us focus on the 4 bands color coded resistor. Every color has its own corresponding numerical value as you see in the picture above. The 1st and 2nd color bands represent the digits of the value. The 3rd band represent the multiplier. Whatever will be the value of the digits, it will be multiplied by the multiply to get its true value. The 4th band represents the tolerance. Tolerance is the acceptable range value of resistor and it is close to the true value. Tolerance is represented by +/- of the true value.

Using Color Coding the determine the resistor’s value.

Example 1.

Here are the colors of this resistor

1st band – orange
2nd band – blue
3rd band – red
4th band – gold

Note: Gold and silver are colors use to represent tolerance. So, if you found gold or silver it means it is the 4th band. This is how to determine which color band is the 1st band.

For corresponding value based on chart

Digit: Orange = 3, Blue = 6
Multiplier: red = 100
Tolerance: gold = +/- 5%

To determine value:

Orange – Blue – Red – Gold
3 6 x100 +/-5%

36 x 100 = 3,600
5% (3,600) = 180
+5%: (3600 +180) = 3,780
-5%: (3600 -180) = 3,420

The answer is:

The resistor value = 3,420Ω – 3,780Ω

Example 2

Here are the colors of this resistor

1st band – brown
2nd band – black
3rd band – orange
4th band – gold

For corresponding value based on chart

Digit: brown = 1, Black = 0
Multiplier: orange= 1000
Tolerance: gold = +/- 5%

To determine value:

Brown – Black – Orange – Gold
1 0 x 1000 +/- 5%
1 0 x 1000 = 10,000
5% (10,000) = 500
+5%: (3600 +180) = 10,500
-5%: (3600 -180) = 9,500

The answer is:

The resistor value = 9,500Ω – 10,500Ω

Example 3.

Here are the colors of this resistor

1st band – red
2nd band – red
3rd band – orange
4th band – gold

For corresponding value based on chart

Digit: red = 2
Multiplier: orange= 1000
Tolerance: gold = +/- 5%

To determine value:

Red – Red – Orange – Gold
2 2 x 1000 +/- 5%
2 2 x 1000 = 22,000
5% (22,000) = 1,100
+5%: (22,000 +1,100) = 23,100
-5%: (22,000 -1,100) = 20,900

The answer is:

The resistor value = 20,900Ω – 23,100Ω

Using Multimeter to determine the value of Resistor

Now, we will use the multimeter to determine the value and we will compare our answers using color coding chart. The reading from multimeter must coincide from the range of value from color coding.

Note: Make sure to calibrate first the multimeter before using. I had posted a tutorial on how to calibrate multimeter last week. Please read for reference. We will assume that every time the multimeter was used, it was already calibrated.

Before reading, we will familiarize the ohmmeter scale of our multimeter.

It is located at the upper most part of our scale. If you notice, the numerical value of the scale is not linear. It means, the distance of scaling is not in uniform. The left side of the scale has a low resolution and the right side has a high resolution.

What is in the resolution?

Resolution is the capability of making an object distinguishable. It is also a measure of fineness which a device can process. So, if we have a high resolution with our scale it will result a much closer reading to the true value. As much as possible, make a reading when a need is in the right side of the scale.

How to increase our resolution?

We can increase our resolution by choosing the right multiplier. If you want your needle to move right, go to higher multiplier. If you want your needle to move left, go to lower multiplier.

Example 1.

Let’s begin to measure this resistor.

We can see that the needle deflection is in the left side. From that point the resolution is very low and can not determine the position from 1k, 1.5k, 2k and infinite. So, go to higher multiplier.

We moved to X10 multiplier and still have lower resolution. Proceed to higher multiplier.

I chose a X1000 multiplier and we see the deflection is in the right side. It is the best time to read the measurement.

The meter reads almost equal to 3.5K or 3,500Ω. This is acceptable from range of 3,420Ω – 3,780Ω

Example 2.

I chose X10 multiplier and this is what we get.

It reads: 9,600Ω
Color coding: 9,500Ω – 10,500Ω

You can also verify the results using digital multimeter. Digital multimeter is much easier because it displays the numerical value on the screen without thinking of the resolution. But, I am using the analog because it is one of the basics that must be knew.

Best wishes,

@thinkingmind

photos are mine @thinkingmind
took from my camera phone.