Re: DVA assembly
DVA Adapter:
http://www.esitest.com/640.html
Plug into Volts (red) and common (black), set scale range per below volts and follow instructions for tests (engine running, cranking, etc.)
Also, see here:
DVA Explained
DVA stands for Direct Voltage Adapter, which is used to measure peak AC voltage. This type of
measurement of AC voltage takes the absolute peak or highest value of the fluctuating AC
voltage signal. Peak readings will be substantially higher than standard or RMS AC values and
are typically used when testing marine CD (capacitor discharge) ignition systems due to their
high variance in frequency as RPM increases and decreases.
An example would be that the typical RMS AC reading of a wall outlet in North America is
120V. However, a DVA measurement of this same AC voltage would reveal that the peak of the
AC sine wave is typically between 160-170V.
Some meters are capable of reading DVA or peak voltage pulses. Many ignition system
components produce short AC voltage pulses. A peak-reading analog meter or DVA adapter
plugged into a digital meter captures and holds the peak value of an AC sine wave long enough
for the human eye to see it displayed on the meter. A conventional meter is incapable of
accurately measuring these short-duration voltage pulses. A peak-reading voltmeter has special
circuits that allow the meter to capture the maximum voltage produced during these short
duration pulses and display the voltage as DVA or peak voltage. Failure to measure DVA can
cause good ignition components to be incorrectly diagnosed as faulty.
The only meters that have built-in peak reading capabilities are analog meters with built-in DVA.
Digital meters do not have built-in peak reading capabilities. In order for a digital meter to read
peak voltage, one will need a DVA adapter, such as CDI part# 511-9773 or 511-9773NL.
Using a DVA adapter, a digital meter must be set to its DC voltage scale. Peak AC voltage is the
measurement, but the DVA adapter has a built-in bridge rectifier, which converts AC to DC. The
DC voltage setting on a digital meter is required to accurately read DVA.