SA5041 Digital Multimeter User ’s Guide
Shijiazhuang Suin Instruments Co., Ltd 16
Chapter 3 Additional Functions
3.1 Return-to-zero Function
Operation guide
(1) Return-to-zero feature makes it possible for user to store a referenced reading, so the display is
a relative value. Press
【
Null
】
key to save current reading value, and the next displayed value is the
difference between measured value and this reference value. Null will light on under this function.
(2) Return-to-zero feature is compliant with all functions.
(3) Press
【
Null
】
key again to exit return-to-zero function, and Null will light off.
(4) If user change to other function, return-to-zero function will be disabled and character Null off.
3.2 Trigger function
Operation guide
(1) External trigger mode
External trigger mode is enabled by pressing the
【
Trig
】
key. Under this mode, there is not any old
data on the display, only if press the [Trig] key, the new measuring period enabled and new data
on the display.
There is no trig function in frequency and capacitance.
(2) Press
【
Auto Trig
】
key to exit trigger mode.
3.3 Mathematical function
Mathematical function of this instrument means calculation of dB and dBm, only working under
AC voltage function.
(1) dB
dB is a unit of power gain. It is relative value. Formula as:
dBV=20log
10
V
in
(2) dBm
dBm is a unit of absolute value of power. Formula as:
dBm=10log
10
(V
in
2
/REF)/1mW
REF takes 600Ω as granted.
Operating Method
(1) Under AC voltage function, press
【
dB
】
key to show dB value on the screen.
(2) Under AC voltage function, press
【
dBm
】
key to show dBm value on the screen.
