WhitakerAudio 60 W Stereo Power Amplifier, Руководство пользователя и по сборке, Страница: 117 / 154

117
60 W Stereo Power Amplifier
operation within the boundary of the curve can be determined by the relation
Where:
R
g 2
= minimum value for the voltage-dropping resistor in ohms
E
c 2
= selected screen grid voltage in volts
E
cc 2
= screen grid supply voltage in volts
P
c 3
= screen grid input in watts corresponding to E
c 2
10.1.2 7027A Beam Power Tube
The 7027A is an 8-pin octal tube used in push-pull power amplifier circuits of high-fidelity audio
equipment. The pinout of the 8-contact socket is given in Figure 10.3. This tube, like other power-
handling devices, should be adequately ventilated. Operating characteristics are charted in Figure
10.4.
( )
2 2 2
2
2
c cc c
g
c
E E E
R
P
−
≥
This curve also applies to types
in which grids #2 and #4 are connected
together within the tube
Grid #2 input expressed as a percentage of maximum grid #2 input rating
100
80
50
40
20
0 20 40 60 80 100 120
Grid #2 voltage expressed as a percentage of maximum
grid #2 supply voltage rating
Area of
permissible operation
Figure 10.2 Grid #2 (screen grid) input rating curve.
Figure 10.3 Terminal pinout of the 7027A.