USING AN OSCILLOSCOPE ON AUTOMOBILES

A digital storage oscilloscope makes it easy to visualize alternating current electrical signals in an automobile. Oscilloscopes have several electrical inputs and control knobs as well as a liquid crystal display (LCD) screen for displaying the signal.

Generally automotive oscilloscopes are used in manufacturing applications by engineers to set electrical signals to the right form. They are also frequently used in garages by mechanics to test the engine’s components for faults. In addition oscilloscopes are increasingly being used by do-it-yourselfers and those looking to make their own automotive repairs. Some examples of electrical signals that one might observe with an oscilloscope are the ignition sequence and the throttle position sensor’s output.

Let’s take a look at how you can use your oscilloscope on your automobile.

Step One

First you’ll need a coaxial cable, which you will connect between the car’s output that you are testing and one of the oscilloscope’s inputs. Most simple digital storage oscilloscopes have two inputs, typically labelled A and B. It doesn’t matter which input you use. You’ll switch the input on by, e.g., pressing either the A or B button.

Step Two

Next you’ll alter the volts/division control in order to change the vertical scale as well as the number of volts for each division. You won’t be able to see the electrical signal clearly on your oscilloscope’s display  until you’ve adjusted the settings appropriately.

Step Three

Now it’s time to adjust the oscilloscope’s time/division (also known as timebase) control which changes the number of times each horizontal division is shown. When you know the electrical signal’s frequency you can accurately calculate the time/division. The time for a single period is T=1/f (with f being the frequency). Then you’ll set the time/division to the calculated value using the equation above.

Step Four

The last step is to adjust the vertical position control, which will move the signal up or down on the oscilloscope’s display. Your goal is to center the signal.

By following these four simple steps you can use your digital storage oscilloscope to observe your automobile’s electrical signals.