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The external
7
1320 volts should not exceed a drain of about 30
milliamps for continuous operation.
Reducing screen voltage of V115 by adjustment of R167 will drop
V115 current drain from about 60 milliamps for 10 watts output
to about 25 milliamps for 2 watts output.
This extra current
may then be used for external purposes.
In summary, when driving an additional amplifier stage from
the exciter unit,
reduce output by adjustment of R167 and
keep C167 and C169 tuned for maximum grid drive in the follow-
ing stage.
o
o
V115 EFFICIENCY
An external jumper is provided on TB101-5&6.
An ammeter may
be connected in series with this jumper to measure V115 plate
current.
B
7
/ voltage has been previously set at
320.
Power input to
the plate circuit of V115 may be calculated from the ammeter
and voltage readings.
The voltage drop across R155 must first
be calculated.
This resistor is in the cathode circuit of
V115,
its value is 250 ohms.
The formula to use would then read:
Power input to plate circuit V115 = I
p
X ( E
p
- ( IR))
Where IR is the drop across R155
If,
for example,
the ammeter reading obtained when connected in
series with TB101-5 and 6 was 60 ma. and 13
7
/ to ground was
7
1320
V.:
Power input V115 = () 6 x ( 320 - (. 06 X 250))
= . 06 X ( 320 - 15)
= . 06 X 305
- . 813 watts
Assuming an output power of 10 watts:
Plate dissipation V115 = Power input - Power output
-
9
-
M6095 Exciter
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