Elma BM 251s-257s
side 48
Electrical specifications
Accuracy is given as +/- (% of reading number of digits) or otherwise specified @
23
o
C +/- 5
o
C and less than 75% R.H.
True RMS model BM257s ACV & ACA accuracies are specified from 5 % to 100 % of
range or otherwise specified. Maximum Crest Factor <3:1 at full scale & <6:1 at half scale,
and with frequency components fall within the meter specified frequency bandwidth for
non-sinusoidal waveforms
AC Voltage
RANGE
Accuracy
50Hz ~ 400Hz
60.00mV, 600.0mV
1.0% + 5d
6.000V, 60.00V, 600.0V, 1000V
CMRR: >60dB @ DC to 60Hz, Rs=1k
Input Impedance: 10M
, 50 pF nominal
AutoCheck
TM
_ACV (BM257s only)
RANGE
Accuracy
50Hz/60Hz
1.000V ~ 1000V
1.4% + 5d
AutoCheck
TM
Lo-Z ACV Threshold:
> 1V nominal
AutoCheck
TM
Lo-Z ACV Input Impedance:
Initially approx. 2.5k
, 120pF nominal; Impedance increases abruptly within a fraction of a
second as display voltage is above 50V (typical). Ended up impedances vs display
voltages typically are:
15k
@100V
100k
@300V
250k
@600V
375k
@1000V
Ohm
RANGE
Accuracy
600.0
, 6.000K
, 60.00K
, 600.0K
0.5%+4d
6.000M
0.7%+4d
60.00M
1.2%+4d
Open Circuit Voltage: 0.45VDC typical
