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Hi
Finn;
Did you read the 768mV P-P with or without your circuit attached?
Attached. I just clipped
the lead into the plug.
What's the counter chip you're using?
CD4522BE IC BCD DIVIDE-BY-N CNTR
16-DIP
I would imagine that
you damaged it in your 20 volt tests, and it now clamps Tracy's output to 0.7V
(typical diaode clamp voltage).
The
one thats being used right now, was never used on the breadboard. I've got 25 of
'em, so I used a different one for no particular reason.
I thought the absolute max (power supply) ratings for CMOS chips (like
4000 and 74C.. series) were 18V.
This one is rated for
20vdc according to the spec sheet.
Certainly TTL chips (74..) are limited to 5V supply (5.25V max).
Either that or you didn't read the scope right.
I
recorded it in memory, and I can interface the scope to my computer and send the
image, for your interpretation. However it is a fairly idiot proof instrument
(that's why even I can make it work :-) as it displays P/P, Max-P & Min-P
along side of the waveform, so it's not even really necessary to interpret the
waveform
I
actually had planned to take it back to the airport and do further testing
tomorrow. I'd planned to use both channel A&B to record the input and output
of the divider chip and record it at various rpm's. After reading your post, I'd
also like to read the output without the counter chip attached.
I finally have an inspection scheduled for noon tomorrow,
so I'll be to busy to worry about this. I'll look into it next week. Now that
Rusty seems to have found a suitable tach, and soon Tracy will be delivering the
EM2 and also is considering a tach output for a conventional tach, this probably
is not really worth the effort, however I will still experiment a little further
if only for the educational value.
S. Todd Bartrim
Turbo 13B RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm
"Whatever you vividly imagine, Ardently desire, Sincerely believe in,
Enthusiastically act upon, Must inevitably come to pass".
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