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IM 11-6625-1589-15-1
3-13 .
LOW DISTORTION .
3-14 .
At frequencies below 200 Hz ,
distortion can be reduced by switching the
NORM / LOW DIST switch on the rear panel to LOW DIST .
In the LOW /DIST mode
the Model 204C will have a longer settling time when changing frequencies .
To
avoid this ,
set the desired frequency before switching to the LOW / DIST mode .
NOTE
The Model 204C output may appear unstable ,
or drop
to zero when turning the frequency dial rapidly or
changing the RANGE switch while in the LOW / DIST
mode .
3-15 .
BATTERY OPERATION .
3-16 .
RECHARGEABLE BATTERY OPERATION .
3-17 .
There is no change in the operating procedure for an instrument in which the
rechargeable battery supply has been installed.
However , this power supply per
mits either ac operation for 115/230 vac + 10% ( selected by switch on rear ) 50 to
400 Hz power sources or battery operation for portable applications.
Battery oper
ation only (with charger power cord disconnected) is required at temperatures below
32 ° F (0 ° C ) and is recommended at temperatures above 104 ° F ( 40 ° c ) .
3-18 .
When the RANGE switch is turned OFF , power is removed from the oscillator
portion of the instrument and a resistor is connected across the output of the power
supply .
The charger will continue to operate as long as the power cord is connected
to a power source .
The resistor , placed across the output of the power supply , acts
as a load in place of the oscillator section to maintain a constant charge rate through
the batteries.
A diode in the output circuit prevents battery discharge when the
oscillator is not connected to a power source .
3-19 .
It is recommended that the power cord be connected to a power source when
ever possible .
This will prevent self - discharge of the battery cells and will assure
a fully charged battery whenever portable operation is required .
Turn the oscillator
OFF when not in use ,
particularly when operating with the power cord disconnected .
3-20 .
When fully charged, the batteries will power the oscillator for approximately
35 hours of continuous or intermittent operation provided they are at a temperature
of 81 ° F £ 10 ° .
If the batteries are operated at higher or lower temperatures their
capacity is reduced as the temperature extremes are approached ; approximately 28
hours at 122 ° F ( 50 °C ) or approximately 20 hours at -4 ° F ( -20 ° C ) .
At temperatures
beyond these extremes the batteries are not capable of supplying their character
istic stable discharge voltage .
3-21 .
The + 122 ° F to -4 ° F temperature range is adequate for most users ,
however ,
keep these limits in mind when operating under field conditions .
Internal temper
atures in excess of 122 ° F are easily obtained if the instrument is left in the sun ,
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