DVA or Peak Reading Voltmeter, what is it and what does it do??

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,073
Got this email from CDI Ignition.
Explains the DVA Meter and attachment for a regular analog meter.
Maybe include it somewhere in the stickies?
Maybe testing stator, trigger etc.??

[FONT=Verdana,Arial,Tahoma,Calibri,Geneva,sans-serif]WHAT IS DVA???[/FONT]

So just what is DVA? More than likely you have heard the term but have never understood exactly what DVA is.

If you have ever called CDI Technical Support for help, more than likely you have been asked to provide the DVA readings of the engine you are working on. Let's take a moment to understand what DVA is and the importance of a DVA reading.

In a nutshell, most 2-stroke Outboard engines have a Stator that generates AC Voltage (Alternating Current). Unlike household current which cycles at 60Hz (Hertz), the Outboard Stator is generating AC Voltage that is in excess of 1,000Hz. At that cycle speed the multimeter isn't responsive enough to capture and display the voltage.

This is where the DVA (Direct Voltage Adapter) comes in to play. The DVA Adapter takes the high frequency AC Voltage and converts it to a DC (Direct Current) Voltage. This allows the meter to capture and display the peak output voltage of the engine. It's as simple as setting your multimeter to DC (Direct Current), plugging in the 511-9773NL (no leads) or 511-9773 (with test leads built in) and you are ready to check the DVA Voltage!

DVA readings are the quickest, most reliable and accurate way to diagnose voltage issues of the outboard engine. Without a DVA adapter or a Peak reading Volt Meter, there is no accurate way to diagnose an ignition system in a timely manner. By using a DVA Adapter you can feel confident along with saving time and money, by diagnosing the failure the first time!

They can be bought on the net, places like eBay, Amazon etc.
Prices start at 90$+

You can make one a lot cheaper.
Search on iBOATS for the directions.
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
16,313
Converts AC to DC is a pretty lame explanation of the functionality.

Perhaps if they gave a real explanation of how you convert AC to DC you would see how ridiculous the price is.
 

Redbarron%%

Chief Petty Officer
Joined
Dec 7, 2017
Messages
479
The DVA does convert AC to DC, but it really functions to take the AC and charge a capacitor to (very close to) the peak AC value even with non-sine wave AC and pulsating dc. The diode converts the AC to DC and the capacitor charges to very near the maximum voltage achieved. The circuits in the CDI actually do the same thing so it really has a meaning in troubleshooting them.
The 2.2 MFD @ 450 volts is charged from the diode and the 1 Megohm resistor is a bleeder that brings that voltage down is it is not being built up during the reading or the cap would hold the peak and not drop correctly. This is the reason I say that the adapter reads very close to the peak.
 

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gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,605
I've built them before. But it doesn't take anyway near $90 dollars to make one. Parts cost are a mere few dollars in you have to buy everything new...
 
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