BATTERY CHARGER UNIT FOR SPECTROPHOTOMETER 
117 V AC 60 CYC. 
SPST SWITCH 
2 AMP. FUSE 
TRANSFORMER #1 
SELENIUM 
RECTIFIER 
0083 N$METER SHUNT 
CIRCUIT 
BREAKER 
3POT SWITCH 
pce VOLT 160 AMP/HOUR STORAGE BATTERY—~ 
RATE OF CHARGE METER 
Za METER SHUNT ¢.0083 1. 
2PDT SWITCH 
CENTER OFF 
+6 +2 - 
DC SUPPLY TO 
SPECTROPHOTOMETER 
2 AMP. FUSE 
TRANSFORMER #2 
SELENIUM 
RECTIFIER 
CIRCUIT 
BREAKER 
3POT SWITCH 
Figure 5.--Wiring diagram (semidiagrammatic) of battery charger unit. 
if the volume of water to be filtered 
is to be kept below 6 liters. The 
measurement of extinction at the vari- 
ous wave lengths has been made less 
time consuming by the construction 
of a cell holder which will accommodate 
as many as four semimicroabsorption 
cells. 
DISCUSSION AND CONCLUSIONS 
While the modifications described 
are not in any sense radical, they have 
greatly simplified the maintenance and 
operation of the DU Spectrophotometer 
both in the laboratory and especially 
on oceanographic research vessels. In- 
struments provided with these modifi- 
cations have given virtually trouble- 
free operation over the past 2 years 
under most severe field conditions. 
The authors have not used the Beck- 
man 14500 battery power regulatornor 
the newer batteryless power supply 
(Beckman 23700) under field conditions. 
These units, especially the latter, have 
not been so employed because they 
would require special skills in repair- 
ing. Furthermore, spare parts for such 
equipment are not generally available 
in foreign ports, whereas batteries 
such as are used in the conventional 
DU Spectrophotometer power supply 
are available almost everywhere. 
MS #1063 
GPO 914508 
