Stereo & Electronics - ma vs. ohms law: vats bypass confussion
07-19-2012, 08:18 PM
okay i simply dont grasp how to read ohms and what resistor to get. I ohm'd the key pellet and came up with .52, i think i selected the wrong ohm reading on the tester. can anyone guide me to exactly what resistor(s) i need?
07-19-2012, 08:32 PM
Look at which ohms setting you put the meter to. 0.52 could be 5.2 ohms, 52 ohms, 520 ohms, 5.2k ohms, 52k ohms, yadda yadda. All depends on what range you set to. If you give us the range we can give you the actual specs and what parts you'd need.
07-19-2012, 08:33 PM
523 ohm. you most likely had it on the kohm scale.
anywhere from 502-564 ohm should work.
07-19-2012, 09:11 PM
when i was looking for the correct resistor there was 1-watt, 1/2 watt, 1/4 watt, etc. what do i need?
07-20-2012, 07:32 AM
The wattage rating is just going to affect how much current can flow through the resistor before it gets hot or smokes. The metal leads will be thicker on the ends, etc.
I don't think any significant current flows through the key pellet, I believe it just has a reference voltage applied to it and the output voltage has to be within a certain range that the PCM is expecting. You should be able to get by with the lowest wattage resistor, but it won't hurt if you use a bigger one (same Ohms value).
If I'm wrong, hopefully WB will step in and correct me. :)
07-20-2012, 07:40 AM
07-20-2012, 08:24 AM
There's a good thread here on passkey II, and a chart with the various resistance values.
07-21-2012, 03:14 PM
since i'm guessing there is not a specific 523 ohm resistor, how close do i need to get?
07-21-2012, 07:28 PM
just put resistors in series to get what you need. If you actually look at the chart in the link I posted, it says what the tolerable resistance range is (502-564).
07-25-2012, 08:46 PM
just to inform others: a 560-ohm resistor did the trick. thanks guys!
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