| T O P I C R E V I E W |
| dewey |
Posted - Jan 06 2008 : 3:46:10 PM
I saw a wiring diagram for an ignition coil, had a transistor symbol on the coil primary negative leg. I was trying to understand how it worked, I guess it worked as a simple bjt switch. The base went to chassis ground, the emitter went to the computer, the collector went to the coil negative leg. The arrow on the lower leg pointed down, isn't the arrow pointed in the wrong direction? I tried to post the wiring diagram, didn't work. thanks |
| 6 L A T E S T R E P L I E S (Newest First) |
| spaman |
Posted - Jan 15 2008 : 7:16:06 PM
the diagram show the transistor as a NPN type but it looks like its wired as a PNP type. |
| dewey |
Posted - Jan 08 2008 : 10:23:32 AM
I tried to cut and paste the diagram and also the address link, I couldn't get anything to work.
In fig. 7 and fig. 9 on the diagram page, there is a transistor on the coil leg in both diagrams. In one, the base leg of the transistor is grounded, in the other, the emitter leg is grounded.
I guess if you follow the electron flow, then the grounded leg is input, the flow has to go against the arrow direction on the emitter leg. In one of those diagrams, the arrow on the emitter leg is pointed in the wrong direction. Does anybody see it that way? thanks |
| Binary 1011001101 |
Posted - Jan 07 2008 : 2:25:13 PM
I suppose you are talking about this diagram here:
And yes it does seem rather messed up that the base goes to ground. The only thing I can think is that the symbol just indicates that there is a transistor in there- it might not be an accurate diagram...
(Edit...Fix image link) |
| dewey |
Posted - Jan 07 2008 : 07:54:00 AM
quote:
Originally posted by Binary 1011001101
Have you got the diagram so that you can post it?
The arrow pointing down on the lower 'leg' indicates that it is a NPN transistor, take a look at the symbol: http://www.markallen.com/teaching/images/electronics/n-p-n-symbol.gif
Yes, the symbol you posted, looks like the one in the wiring diagram. I have looked at several basic tutorials on using this transistor as a basic switch, following conventional flow, all current has to follow the arrow, so with the base grounded, there is no flow to the base, the transistor is useless. At least that is the way, I see it. thanks |
| dewey |
Posted - Jan 06 2008 : 4:53:50 PM
I tried to post the wiring diagram, couldn't get it to work. With the NPN transistor, I understand that to mean, the base is positive and that small current moves from the base to the emitter. They can't ground the base leg, in that example, can they?
As far as posting the wiring diagram, I tried to highlite the diagram in order to copy and paste, couldn't highlite it.
I can tell you how to find the wiring diagram. Go to autozone.com, click on (vehicle repair guides) 96 dodge stratus 2.5l engine. On the next page, toward the top, click on vehicle repair guides. next page, click on chassis electrical, next page, right hand column, scroll down to wiring diagrams, click.
I appologize for not being able to post the diagram, this is an old P3 computer and I can't get it to co-operate. I guess I'm not computer literate. thanks for the reply |
| Binary 1011001101 |
Posted - Jan 06 2008 : 4:35:07 PM
Have you got the diagram so that you can post it?
The arrow pointing down on the lower 'leg' indicates that it is a NPN transistor, take a look at the symbol: http://www.markallen.com/teaching/images/electronics/n-p-n-symbol.gif
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