Data set 01
1956 Western Electric Tubes
Published operating points and test conditions from this source.
SECTION 1
Pentode
Characteristic
HeaterOrFilamentVoltage
5.5 V
HeaterOrFilamentCurrent
1 A
Other
Typical Power Output
6 W
ClassC;ScreenModulated
Power - Pentode (NOT beam) ·Pentode
307A
Power pentode designed primarily for Class-C radio-frequency transmitting, amplifier, oscillator, or modulated RF service.
Directly heatedCold cathodeCommon cathodeDissimilar
- Sections
- 1
- Base
- -
- Socket code
- UX4
- Base pins
- 4
- Nominal heater
- 5.5 V / 1 A
Description
Air-cooled transmitting pentode for Class C RF screen-modulated service.
Socket description
Medium-shell UX 4-contact
General specifications
Tube and section characteristics
Properties common to every published source and operating point.
Heater and base
- Base
- -
- Socket code
- UX4
- Base pins
- 4
- Nominal heater voltage
- 5.5 V
- Nominal heater current
- 1 A
- Parallel heater voltage
- -
- Parallel heater current
- -
- Series capable
- No
Terminal pinout
Electrical assignments shared by every tube using this base designation.
No verified pinout is recorded for this base designation.
Section ratings
1 physical section, each with unique specifications.
Section 1
Pentode
X-ray radiationInterelectrode capacitances
- Transconductance
- 0.004 S
- Max plate voltage
- 500 V
- Max screen voltage
- 300 V
- Max plate dissipation
- 15 W
- Max screen dissipation
- 6 W
- Max cathode current
- 60 mA
Promoted fields audited from printed ratings/characteristics; remaining published values preserved as parameters.
Source-dependent data
Operating conditions by source
Each block preserves the test conditions and published values from one reference. Values from different sources are intentionally kept separate.
Data set 02
2026 Western Electric 300s
Published operating points and test conditions from this source.
SECTION 1
Pentode
Characteristic
Filament voltage
5.5 volt
Filament voltage 5.5 volts, a.c. or d.c.
as functions of plate voltage in Figures
5 volt
as functions of plate voltage in Figures 5 and 6, respectively, for a screen-grid voltage of 200 volts
respectively, for a plate voltage of
500 volt
respectively, for a plate voltage of 500 volts, a screen-grid voltage of 200 volts, and several values
voltage on positive swing of input +
30 volt
voltage on positive swing of input +30 +30 volts
For continuous operation the direct plate current should be limited to
45 milliamperes
For continuous operation the direct plate current should be limited to 45 milliamperes.
**Carrier conditions for use with a modulation factor up to
1
**Carrier conditions for use with a modulation factor up to 1.0.
Because of secondary emission eflFects, the suppressor grid should not be driven more than
20 second
Because of secondary emission eflFects, the suppressor grid should not be driven more than 20
mended values of load resistance and the indicated range of input voltages. In designing the
307 volt
mended values of load resistance and the indicated range of input voltages. In designing the 307A
Direct plate voltage
500 volt
Direct plate voltage 500 500 500 volts
Direct screen-grid voltage (approx.)
200 volt
Direct screen-grid voltage (approx.) 200 250 250 volts
Screen-grid circuit resistance
14000 ohms
Screen-grid circuit resistance 14000 20000 20000 ohms
Total control-grid bias (approx.)
-3 volts
Total control-grid bias (approx.) - 3 5 - 3 5 — 35 volts
Control-grid circuit resistance
10000 ohms
Control-grid circuit resistance 10000 10000 10000 ohms
Fixed control-grid bias
-2 volts
Fixed control-grid bias - 2 0 - 2 0 — 20 volts
Suppressor-grid bias o
0 volts
Suppressor-grid bias o 0 0 volts
R-F control-grid voltage
50 volt
R-F control-grid voltage 50 50 50 peak volts
Direct plate current
40 milliamperes
Direct plate current 40 4 5 60 milliamperes
Direct screen-grid current
20 milliamperes
Direct screen-grid current 20 12 13 milliamperes
Direct control-grid current
1.5 milliamperes
Direct control-grid current 1.5 1.3 1.4 milliamperes
A-F suppressor-grid voltage
50 volt
A-F suppressor-grid voltage 50 0 0 peak volts
Effective load resistance
4000 ohms
Effective load resistance 4000 6500 5000 ohms
Carrier power output
6 watts
Carrier power output 6 15 20 watts
Power output on a-f peaks
24 watts
Power output on a-f peaks 24 — watts
Note
1
Note 1—Carrier conditions for use with modulation factors up to 1.0.
voltage of
50 volt
voltage of 50 peak volts. Corresponding plate current, screen-grid current, control-grid current,
; SUPPRESSOR-GRID VOLTAGE
0 VOLT
; SUPPRESSOR-GRID VOLTAGE -0
F
2 SECOND
F2 = SECOND HARMONIC OUTPUT VA Z
F
3
F3 «= THIRD HARMONIC OUTPUT
Si!::::::::::::;!!: iSiSSSsi:;!:: LOAD RESISTANCE =
4000 OHM
Si!::::::::::::;!!: iSiSSSsi:;!:: LOAD RESISTANCE = 4000 OHM S
CONTROL-GRID VOLTAGE =
-20 VOLT
CONTROL-GRID VOLTAGE =-20 VOLTS
SCREEN-GRID VOLTAGE
-250 VOLT
SCREEN-GRID VOLTAGE -250 VOLTS
CONTROL-GRID VOLTAGE »
-35 VOLT
CONTROL-GRID VOLTAGE » -35 VOLTS (APPROX)
SCREEN-GRtO VOLTAGE «
200 VOLT
SCREEN-GRtO VOLTAGE « 200VOLTS (APPROX)
LOAD IMPEDANCE
-4000 OHMS
LOAD IMPEDANCE - 4000 OHMS
Other
Maximum direct plate voltage
500 volt
Maximum direct plate voltage 500 500 500 volts
Maximum direct screen-grid voltage
300 volt
Maximum direct screen-grid voltage. 300 250 250 volts
Maximum direct plate current
60 milliamperes
Maximum direct plate current 60 60 45 milliamperes
Maximum direct screen-grid current
25 milliamperes
Maximum direct screen-grid current. 25 25 25 milliamperes
Maximum direct control-grid current
7 milliamperes
Maximum direct control-grid current 7 7 milliamperes
Maximum plate dissipation
15 watts
Maximum plate dissipation 15 15 15 watts
Maximum screen-grid dissipation
6 watts
Maximum screen-grid dissipation... . 6 6 6 watts
Maximum direct plate voltage
500 volt
Maximum direct plate voltage 500 300 volts