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Showing posts from June, 2014

Build Your First Robot - Reading Resistors

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This post will be the concluding post for resistors. In this post I will mainly concentrate on reading the value of a common resistor. This post should have been the second post in the resistor series but as I was keener in going into the math and principle behind resistors, I completely forgot to write this post.

As resistors are very small, printing their values on them was too difficult and costly in the olden times. Hence they resorted to print colored bands on the resistors that later could be used to interpret their values. There are usually four bands on a resistor. The first band gives us the first digit of the total resistance. The second band gives the second digit of the resistance. The third band gives the number of zeros. The fourth band tells us the percentage by which the actual resistance of the resistor would vary compared to the printed value.

For resistors with 5 or 6 bands, you can use this chart to interpret their values.

Build Your First Robot - Resistors in series and parallel

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In the last post, we learnt the way of calculating resistance required in a circuit. In today's post, we will discuss about the different combinations in which resistors can be placed to obtain any non-standard resistor values.

Resistors in Series As the name suggests, here the resistors are placed in series. In this type of configuration the potential differences across each resistor would be different and would be directly proportional to the value of the resistor. More the resistance, more would be the potential difference. The current through the circuit would be constant. Hence, from this observation:
Vt = V1+V2+V3+.....+Vn Therefore, IRT = IR1+IR2+IR3+......+IRnHence, RT = R1+R2+R3+......+RnResistors in parallelIn this type of configuration, the ends of two more resistors meet. Here the current across the ends of resistors varies depending on the value of resistance. More the resistance, less would be the current. The potential difference across the resistors is the same. Henc…

Build Your First Robot - Resistors and Math

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In the last post we came to know what a resistor is and why it is used in electronics. In today's post we will learn about the math that is associated with these resistors. The unit of resistance is called ohms.

Voltage is directly proportional to current, which means more the voltage, more will be the current. Hence
V/I = R

where V is potential difference (voltage)across the resistor,I is current and R is the resistance.

We will know apply the formula we just saw.
1. Say you have a resister wired up in a closed circuit. The potential difference is 6 volts and the current flowing through the circuit is 2 amperes. Calculate the resistance of the resistor.
Ans- We are given that the potential difference across the 2 ends of the resistor is 6v. We also know that the current flowing through the circuit is 2 amps. Hence by using the formula V/I =  R
6/2 = 3 ohms.

Note:- While using the formula, all the units must be in SI system.

2. An led operates at 3 v and requires current not more …

Build Your First Robot - Resistors

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In this series we will learn the basics that a person requires to a build a robot. In today's post we are going to discuss about resistors. Now you might have heard about resistors and perhaps would have wondered what are they? Today we will find that out. Analogies are the best ways to understand anything. We are going to apply the same technique and understand what a resistor is, along with few more fundamental concepts in electricity.  Let's dive in!

To understand what a resistor is, we need to know what voltage and current are. Water analogy is a popular analogy to understand voltage, current and resistance. Think of the battery as a water tank full of water. Now imagine a pipe attached at the bottom of the tank. If the pipe is open the water will flow out due to the "potential difference". The water always flows from a region of higher potential to a region of lower potential. The same is with current. In the water analogy the potential difference determines how…

Periodic Table in C

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I recently created a program to digitize periodic table and I wanted to share it with the world. In this program, the user can choose to input the name of the element to get its valency and atomic number or the user can simply input the atomic number of the element to get its name and valency.
Here is the code:
Periodic table in C

Here is the software version of it:
Periodic Table.exe