Power
Note1 For safety reasons, only an approved adaptor may be
used; use of any other will void the guarantee. In some
countries, the correct Sinclair adaptor may not be
available in which case, the dealer will supply an
alternative approved unit.
Note 2 For disposable cell operation, 4off Csize cells should
be used. If possible, high power or Alkaline batteries
should be used. Alist of suitable types is given below
—ask your dealer if in doubt. To obtain long battery
life, the display brightness control (10) should be set
to the minimum acceptable level and the meter switched
off whenever measurements are not being made.
In the 'disposable' position, inserting the power jack
will automatically disconnect the internal batteries. In
the 'rechargeable' position, inserting the powerjack will
cause the internal batteries to be charged. This charging
will take place at constant rate whether the instrument
is switched 'on' or 'off’.
Disposable Batteries
Suitable cells for use in the DM35O and DM450 are as follows:
Size Classification: ASA IEC Japan
CR14 AM2
Normal Types: SP11, 835, 120, V8735, 114, 110LP,
214, U11 MJ
High Power Types: HP11, 935, 814, V5035A, M14-F, 111,
IC, 27
Alkaline Types: Mn 1400, E93, AL-1, VS1335
Rechargeable Batteries
Special Sinclair rechargeable units are available. Full instructions
for use are provided in the pack.
Low Battery Indication
Indication of failing batteries is provided by flashing of the
display. This occurs when the voltage falls below 4.4 volts, and
gives some time to continue making measurements before reading
errors will occur.
Rechargeable batteries should not be allowed to fully discharge.
Weak or dead disposable cells should never be left in the instru-
ment since they may leak damaging chemicals.
Zero
Both instruments have automatic adjustment of zero. Zero offset
can, however, occur as follows:
DC: Leakage currents of up to -. ZOOpA can cause
offsets on the 200mV and 2V ranges which will
disappear when alow impedance source is con-
nected. On the DM450 azero reading of up to ,l_
0.02% of range may appear on 200mV, 20V, and all
DC current ranges. This is allowed for in the speci-
fication but can be subtracted from the reading to
obtain amore accurate result.
On 2000mV ultra high impedance, azero will not be
obtained until the input is connected to an external
impedance.
AC: Zero reading should be disregarded until asource is
connected. Zero reading of up to 10.1% of range
may occur on the 20 volt and 200mV ranges. This
should not be subtracted from the reading.
Resistance: On the 2009 range, shorting out the leads will
produce anon zero reading, which should be
subtracted from the measurement reading.
