ECOTEST DKG-21 Operating Manual page 10

3.2.11.1 The minimum time of DE measurement expressed in seconds,
when the main relative permissible error limit of measurement complies
with the requirements of 3.2.4, does not exceed the value, calculated by the
formula:
H 
( 10
where
p
3.2.12 Continuous operation time when powered from freshly charged
storage battery under normal background is at least 3000 hours.
3.2.13 Unstable readings during 8 hours of continuous operation, not
more than 5 %.
3.2.14 The dosimeter is powered from Li-ion storage battery of 3.2 to
4.2 V voltage and a rated capacity of 120 mAh.
Note. Operating DC supply voltage - 3.7 V.
 
36000
 
= +
t 60
 

H ( 10 )
 
p
- is a numeric value of DER in µSv/h.
)
,
8
(1.2)