Taylor 45C - Valve Data; 4;1 Method of Working out Settings

3/7
GAS.
BUTTON
When knob A is fully clockwise
the
meter is
shunted
to
approximately
500
fxA.
full
scale
.
The grid resistor
is 270
kilohms,
so
with
a
low
slope
valve
the
usual
grid
current
limit
of
2
fxA.
produces
a voltage change of
0-54
volts
which
is likely
to
cause
an
I
a
change
of
about
0-54
mA. With a
high
slope valve
the grid
current is
usually
limited
to
0*7
y.A. which
produces
0-19
volts
which is
likely to cause
about the
same I
a
change.
4. VALVE
DATA
4/1
METHOD OF
WORKING
OUT SETTINGS
The Valve Chart,
published,
separately, gives data
for nearly
3000
valves,
but new
types
are
constantly
being
added. Space is
left for
the
user
to
fill in
settings for
new
types
as
these
are
encountered.
The settings are
easily
worked
out
as follows.
It
is assumed
that
manufacturers'
data
is available as to base connections
and
electrical
characteristics.
Column 1
2
3
4
5
6
7
8
9
10
Valve
Type
Manufacturer
Holder
No.
Base
Type
Heates
Volts
Type
Voltages
Cap
ABC
Selectors
Mutual
Conductance
Columns
1,
2, 3,
and
4
are
filled
by inspection.
International
Octal
based
valves
with
heaters to
pins
2 and
7
are
tested
in
No. 12 holder
(108/1)
but those
with
heaters
to pins 7
and
8 are
tested in
No
. 13
holder
(108
/2)
.
Similarly
miniature
7 -pin
based
valves with heaters
to
pins
1 and 7 are
tested
in
No.
15
holder (B7G/1)
but
those
with
heaters
to pins
3
and 4 are
tested
in
No. 16 holder
(B7G/2).
Columns
5
and
6
are
filled in from manufacturers
data.
In Column
7
enter
suitable
test
voltages
as follows
:
—
60V.
anode/60V.
screen
—
small
triodes and
pentodes,
high
dissipation
triodes and
pentodes.
100V. anode
/60V.
screen
—
small
triodes and
pentodes, high
dissipation
triodes and
pentodes and
R.F. pentodes.
100V.
anode
/ 100
V. screen
—
small
triodes,
high
slope R.F.
pentodes,
most output
pentodes.
200V.
anode
/100V.
screen
—
high mu triodes,
normal R.F.
pentodes.
250V.
anode
/200V.
screen
—
high
mu triodes,
R.F.
pentodes with
high rated screen
voltage.
11