Welcome to

Mr. Bradford's

Automotive Services I

Class

Diagnosing today’s automobiles is a very complex task.  Today’s automobiles come equipped with up to 70 computers networked together to exchange a very large number of sensor inputs that in-turn affect how the car runs, if at all.  Technicians must be trained in electronic theory and basic computer operation to be successful diagnosticians.

!!!!LET'S GET STARTED!!!!

The first step in learning how sensor input and computer output determine if a car runs great or poorly is to understand basic electronics. Below I have put together a seven task webQuest to assist in your learning enjoyment.
Volts, Ohms, and Amperes are the terms used to represent the variables in electric circuits.
  • Voltage is the pressure applied to a circuit to set electrons in motion to do the work that we want the energy to accomplish. This electrical pressure is measured in Volts and is often represented as E and V.
  • Ohms are the resistance offered in a circuit to the movement of electrons in a circuit. (HINT: electrons are not stupid…they will always take the path of LEAST resistance.) This resistance is measured in Ohms and is often represented as R and L.
  • Current is the quantity of electrons moving in a circuit and is directly proportional to the amount of voltage applied and indirectly proportional to the resistance offered by the circuit. Current is measured in Amperes and is often represented by A and I.

For a different perspective and explanation, click on the following link and read the information on (What are amps, watts, volts and ohms?) then return for step two.

How Stuff Works

  
To be successful in troubleshooting, technicians must understand ohms law and the relationship each variable has on the overall circuit behavior. Next we will look at other perspectives in gaining the knowledge that we will need to know to understand ohms law.
The circuit at the right is a simple series circuit. Analyze the relationships of the voltage, current, and resistance. Now, look at the circuit below and the relationships of the same variables. By clicking on the image below your browser will be directed to a website to see an animation of the effect of adding in a parallel circuit path.

Please return for task three.

 
Ohm's Law is V = I x R where V = Voltage, I = Current and R = Resistance. So, it is easy to see that algebraically we can arrange this formula to find:
  • I=V/R
  • R=V/I.

Now let’s go see some calculations. Click HERE.

 

!Welcome Back!

Review the use and explanations listed on this website (!CLICK!); then using the values to the right, substitute the variables using your pencil and paper. This assignment will be handed in tomorrow.

   1. V=12, I=2, R=? 2. R=10, I=1, V=?

3. I=4, R=100, V=? 4. V=120, I=2, R=?

5. I=0.250, R=100, V=? 6. V=100, R=1000, I=?

Now, let's look at the three circuit types, and how to use a meter to measure the variables. That's right there are only three circuits!! This is a “breeze”, right?
A Series circuit has only one path for current to flow/(to pass through).  

A Parallel circuit has two paths for current to flow/(to pass through).  
A combination of a Series and a Parallel circuit has one path that all current flows then the current branches into two or more paths to flow/ (to pass through). Hint: Click on the Combo Circuit to see more.  
To Measure Amperes of current, the meter must be connected in series. This means the meter is connected in the circuit.  
To Measure Voltage in a circuit, the meter must be connected in parallel to the circuit.  
To Measure Resistance in a circuit, TURN OFF THE POWER FIRST, then connect the meter in parallel to the device or component to be measured.  
NOW, Let's REVIEW!
Follow the link below.  It will carry you to a website that will allow you to see the effects of changing the electrical variables and their relationships in real time. 

HERE! HERE! HERE!

Now try this one!!!!!!!!!!!!!!!!

You Know What to Do

Please continue this assignment by going to Autoshop 101, select Online Instruction, then select, Electrical Fundamentals. Have FUN!!!