 Very very electrical question., Tachometer waveform |
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| sgomes |
  Sep 3 2004, 09:24 PM
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#1
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Electric Member  Group: Members Posts: 815 Joined: 6-May 04 From: Campbell, CA Member No.: 2,029  |
Ok, I don't expect to get an answer to this question but here goes nothing:
I've got this fancy tacometer drive thingy that is supposed (IMG:style_emoticons/default/unsure.gif) Assumptions about the tach: It expects at least +5V pulses more is ok. It assumes a four cylinder engine. My assumption on how tachs work: You get one pulse for every spark. So..... assume 6000rpm for the sake of argument 6000rpm= 100 revs per second * 60 seconds 4 sparks per revolution. 4 * 100 = 400 pulses per second. I've got something close to 200 pulses per second comming out of my sender at about +10V. The tach isn't moving. |
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| JeffBowlsby |
Sep 4 2004, 08:14 AM
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#2
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914 Wiring Harnesses & Beekeeper Group: Members Posts: 8,974 Joined: 7-January 03 From: San Ramon CA Member No.: 104 Region Association: None 
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So I have a dumb question...
Why does an electric car need a tach anyway? Couldnt the shift points just be read off the speedo? (IMG:style_emoticons/default/confused24.gif) |
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Posts in this topic
sgomes Very very electrical question. Sep 3 2004, 09:24 PM
lapuwali There aren't four sparks per crank revolution.... Sep 3 2004, 09:37 PM sgomes Thanks! There is always a factor of two in the... Sep 3 2004, 09:42 PM jkeyzer 5V square wave will NOT work with anything but the... Sep 4 2004, 12:10 AM sgomes Looks like I'll have to look into a 74 or late... Sep 4 2004, 03:39 AM BIGKAT_83 After I converted my 74 914 tach for a V8 operatio... Sep 4 2004, 06:30 AM lapuwali Why does an electric car even need a gearbox? I u... Sep 4 2004, 09:11 AM
sgomes Bowlsby (Jeff? isn't it?) :
Yes, I could just... Sep 4 2004, 10:41 AM |
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