Week 3 "test boards complete and testing a sensor"

During this last week of class we finished up the last of our relay test boards and were each given a sensor out of a box and asked to find out what kind of sensor it was and test it if possible.This was the sensor I was given. As soon as I was given this sensor I was pretty sure I new what it was. I thought it was a wheel speed sensor and it was.

After looking up the number on the sensor I learned that it was on fact a wheel speed sensor. This is a Wabco S+ sensor for a Benz Truck specifically a wheel speed sensor for the ABS system.








The next thing was to figure out how to test this sensor. I really had no clue where to start, so I got on you tube and was able to find out how to test wheel speed sensors either on the vehicle or off. Below is the a link to the video that helped me understand what I was doing.
 .https://www.youtube.com/watch?feature=player_detailpage&v=7eCJa7JZzfg

Here is is a picture of me testing the sensor for resistance, now as far as I could tell from my testing, the sensor I was given was open some where. It was a bad sensor. I was unable to find what the resistance that this particular sensor should have measured at, but it didn't matter because the meter read nothing. It was a cool assignment though I can now say I know how to test wheel speed sensors, something I could not have said the week before.

Another one of our assignments was to color in the schematic on the left. This would be the schematic we would use to help instruct some our newer class mates on wiring up light boards for what would be our final. Me and my group spent a good hour and a half talking and discussing the right way to color in the diagram. After some time and a little help from another one of our peers we were confident that we had the schematic colored in right and would be ready for the light board.


I think the thing I can reflect the most on this last week was how important the ability to discuss and work as a team can be. We sometimes tend to ignore others input due to our own confidence. This can be a great downfall if you are wrong in what you think. For me it was the simple mistaking a relay for a switch while coloring our wiring diagrams, I was so confident that I had it right and my group had it wrong that I had to go verify with another group and guess what I was the one who was wrong. This is where if I would have just put my ego aside I would have understood what my group was saying and not have been the jackass.

Week 3
Hours 18
Quarter Hours 52

"Relays, Diodes and learning how they work"

During the second week of instruction my instructor began to bring up relays and diodes. I remembered a lot about these things from a couple of previous electrical courses but just like everything else if I'm not using it or studying it it tends to go to the back of my brain. Needless to say I had some relearning to do. My instructor gave some really good lectures on relays and and what they are used for and also how they work. During our lab time while working on our relay test boards he also came over and began talking about diodes and what they are. He then showed me and several other students how to test a diode using a multimeter. Along with the class discussions and conversation with my peers, There were a couple of videos on you tube that helped my understand how diodes and resistors work.

 Below are pictures of me testing a diode using a multimeter and in this case on this test board there was an open diode.

Here are a couple links to some of the videos that helped my understand what was really going on inside a diode and a resistor.
www.youtube.com/watch?v=DUiNq7P...
www.youtube.com/watch?v=JBtEckh3L9Q‎

Here is another link to how light emitting diodes work.
www.youtube.com/watch?v=8quZrUcRFlw‎‎


This last week I also had the task of continuing to test switch boards, this time the boards had relays on them. What we were looking for on the boards was open circuits, high resistant voltage drops and shorts. I found this to be difficult at times and pretty straight forward others. It was another one of those things where I had to keep track of the steps I was taking and make sure I was going in the right order. When I did that things worked out fine. Below are some picture of some of the testing I was doing.

 In the pictures above I found an open circuit on the + side of the circuit. this was just one of many boards tested.

I think the thing I can reflect the most on the most over this last week was some of the discussions I had with some of my peers while working on test boards. I would here someone say "oh it's a bad relay on this one" and for some reason several times I asked different people that would say this, "well why is it bad?". This would prompt a discussion. This is when I feel that my understanding of relays and diodes and how to test them came to help me understand more about them while hopefully helping someone else with the same. It seems to me if some thing is broken I can probably fix it but I  also feel I have an obligation to try and figure out why it broke or isn't working. WHY, WHY, WHY

Week 2
Hours19ish

WK 1"finding open circuits, high resistent voltage drops and shorts"

Spring quarter just started and we are jumping right into Electrical. During the first week of instruction we began talking about current flow, had a nice discussion and exercise on electrons and how they flow. We also talked about resistance in which Jeff gave us nice demonstration by burning up some wires. It was a great beginning to the quarter. We also discussed Kirchhoff's law and said our prayer many times, "no current flow, no voltage drop!!!!"  Our assignments for the first week mostly had to do with determining whether or not we had open circuits or high resistance voltage drops on light and motor test boards.

Above is a picture of a light board with a HR/VD or high resistance voltage drop which I was able to located on the power side of the circuit. Below is two pictures of a similar test board which had an open circuit on the ground side that I was easily able to identify.

Apart from just doing light test boards we also worked on finding similar problems on motor test boards which a basically the same thing. how ever at the end of the week we were asked and shown how to locate short circuits on test boards both light and motor. At first I thought oh this will be much easier than the last time I had to do this and it was. I'm not saying that shorts are easy to find but going through similar motions with a better understanding made it much easier this time.

I think the highlight of my week was being able to help others understand the electrical we are studying a little better and maybe learn a little from the help I was able to provide to some of my peers. The main thing I learned during this week was that when some thing seems to be working just fine and you cant find the problem even though you know there is one, is to go back to the beginning/the basics. This came about when I had a problem with a motor test board, the problem was that everything seem to be just fine. My first though was oh this test board must just be a joke, I went and grabbed my instructor for some help. He came out asked what the problem was and I told him. He switched the first switch on the board that was supposed to open the circuit and it didn't. He simply looked at me and walked back to his office. I think he saw the look on my face, the duh look. I new right away what the problem was, me not starting out in the beginning/ the basics.

WK 1
Hours 18