SunPro Digital Meter info

[steveb@newkla.kla.com (Steven Buchholz)]

I have a SunPro Model CP7678 meter.  It comes in an orange case.  It has 
settings for: DC Voltage, DC Current (15A), Resistance, Diode Check, Lo 
Tach, Hi Tach (x10), Dwell and Duty Cycle.  The Tach and dwell settings 
have 4,5,6 and 8 cylinder settings.  It is water resistant and will auto-
matically shut itself off after not being used for a few minutes.  

I was thinking about getting one of these things for my father for Christ-
mas, and I saw it for sale at Sears for $100, which appears to be the list 
price.  I got mine on sale a few years ago for ~$55, and Nick told me he 
recently bought one on sale in the $60 range.  

There are other options as well.  As was pointed out by someone else, you 
can take advantage of the fact that a standard D'Arsonval (analog) meter 
responds to average voltage.  By taking a reading of a pulse-width modulat-
ed DC voltage with a standard DC voltmeter and dividing that value by the 
peak DC voltage (12V(?)) and then multiplying by 100, you will get the duty-
cycle in per-cent.  I noticed in the original EC article that the pictures 
showed some Radio Shack digital meter that has duty-cycle as well.  I had 
not seen this meter in my local store before so I don't know the price.  
If you don't need the dwell angle capability (which could also be computed 
BTW) either of the two options would be acceptable.  

Steve Buchholz
s_buchho@kla.com