Page 313
CIRCUIT DESCRIPTION
The function of this circuit
is
to amplify the driver output asured by the 100 ohm resistors acros the input and
to the 100-watt level. Basically,
it
consists of two push-pull output circuits. Hybrid combiners areussd to split the drive
pain combined into one amplifier.
power
between pairs and to combine the outputs of the
two
amplifier pairs.
Q951
and 0952 comprise one push-pull pair, and Q953 and
0954 the other. Bias
is
applied to the input transformer
The power amplifier, like the driver,
is
broadband, with
-
center taps, and
is
derived from
a
heat-sink mounted diode.
essentially flat response from
3
to 30 MHz. Harmonics are
~~
/
As the diode
is
mounted on the same heat sink as the power
Xenuated by the low
pass
filter (board~x and additional
amplifier, the bias voltage tracks the power amplifier selectivity
is
not required.
It
is
this characteristic that makes
temperature, preventing thermal runaway. Power balance
is
the "no-tuneup" feature possible.
iibJ
7
-
i)~r)F
POWER AMPLIFIER SCHEMATIC
CIRCUIT
BOARD
H
Refer
to
Page
282
for
Schematic symbols.
HEATH
PART NO.
41
7-831
TRANSISTORS
a951
-Q954
QUAN-
TlTY
4
TYPE
*
2N6456
or
S30-12A
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