Urrea UD87 Manual De Usuario página 36

E N G L I S H
To take the combined AC+DC total RMS
Volts measurement, press the menu key
4. In the above example the total RMS of
6.1188 V shows on the primary display and
the frequency of 60.00 Hz shows on the
secondary display. When calculating the
power dissipated in a circuit component, it is
critical that the DC value is factored into the
equation VRMS x IRMS, where VRMS is AC +
DC total RMS.
Another useful feature of this Meter is AC/
DC dual display mode. AC voltages riding
on power supplies can cause problems with
electronic circuits. If the Meter is set to DC
Volts mode, the
display shows the DC component of 6.0000V.
However, the AC component may be missed.
It is recommended that you set the meter
to AC/DC dual display mode by pressing the
menu key 4 twice. The primary display shows
the 1.2000 V AC voltage and the secondary
display shows the 6.000V DC voltage. That
is, AC/DC mode allows you to simultaneously
make AC and DC measurements without
changing the meter settings.
Frequency (Hz) Measurements
The meter autoranges to one of six frequency
ranges: 50.000 Hz, 500.00 Hz, 5.0000 KHz,
50.000 KHz, 500.00 KHz and 5.0000 MHz.
The meter beeps to indicate when a particular
pushbutton is not allowed when measuring
frequency. The 1ms Peak button cannot be
36
used.
Measurement:
Menu key:
Connect leads:
Primary display:
Secondary display:
Measurement:
Menu key:
Connect leads:
Primary display:
Secondary display:
Measurement:
Menu key:
Connect leads:
Primary display:
Secondary display:
* The meter defaults at negative edge
triggering in the frequency measurement
mode.
When you set positive edge triggering by
pressing the Menu key 4,
in the secondary display.
* You can turn on positive or negative duty
cycle by pressing the Menu key 4.
Duty Cycle Measurements
Duty Cycle (or Duty Factor) is the percentage
of time a signal is above or below a trigger
level during one cycle.
The duty cycle mode is optimized for
measuring the ON or OFF time of logic and
switching signals.
Systems such as electronic fuel injection
systems and switching power supplies are
controlled by pulses of varying width, which
can be checked by measuring duty cycle.
Frequency
(no selection)
(fig. A)
Hz
Frequency and Duty
Cycle dual display
%
(fig. A)
Hz
Duty Cycle (%)
Frequency and Pulse
Width dual display
ms
(fig. A)
Hz
Pulse Width (ms)
is displayed