25CA5

Miniature beam-power pentode designed primarily for audio-frequency output stages in television and radio receivers, offering high power sensitivity at low plate and screen voltages.

Directly heatedCold cathodeCommon cathodeDissimilar

Sections: 1
Base: 7CV
Socket code: -
Base pins: 7
Nominal heater: 25 V / 300 mA

Description

The 25CA5 is a miniature beam pentode designed primarily for audio-frequency power-output stages in television and radio receivers, with high power sensitivity at relatively low plate and screen voltages.

General specifications

Tube and section characteristics

Properties common to every published source and operating point.

Heater and base

Base: 7CV
Socket code: -
Base pins: 7
Nominal heater voltage: 25 V
Nominal heater current: 300 mA
Parallel heater voltage: -
Parallel heater current: -
Series capable: No

7CV - Terminal pinout

Electrical assignments shared by every tube using this base designation.

Terminal	Section	Connection	Evidence
PIN1G3	A	G3 — Suppressor GridGroup 7CV1 EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN1K	A	K — CathodeGroup 7CV1 EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN2G1	A	G1 — Control Grid EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN3H	—	H — Heater EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN4H	—	H — Heater EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN5G1	A	G1 — Control Grid EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN6G2	A	G2 — Screen Grid EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV
PIN7P	A	P — Plate (Anode) EIA chart transcription; independent manufacturer verification pending	Unverified EIA Base Connections, printed page 128, 7CV

Section ratings

1 physical section, each with unique specifications.

Section 1

Beam Power

X-ray radiationInterelectrode capacitances

Plate resistance: 15000 Ω
Transconductance: 0.0092 S
Max plate voltage: 130 V
Max screen voltage: 130 V
Max plate dissipation: 7 W
Max screen dissipation: 1.4 W

Published source values promoted where applicable.

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 01

1961 Tung Sol

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Other

Heater voltage
25 V
Nominal
Heater current
300 mA
Nominal
Plate voltage
110 V
ClassA; OperatingPoint1
Plate voltage
125 V
ClassA; OperatingPoint2
Screen voltage
110 V
ClassA; OperatingPoint1
Screen voltage
125 V
ClassA; OperatingPoint2
Grid 1 voltage
-4 V
ClassA; OperatingPoint1
Grid 1 voltage
-4.5 V
ClassA; OperatingPoint2
Load resistance
2500 ohm
ClassA; OperatingPoint1
Load resistance
4500 ohm
ClassA; OperatingPoint2
Maximum-signal power output
1.1 W
ClassA; OperatingPoint1
Maximum-signal power output
1.5 W
ClassA; OperatingPoint2

Characteristic

Plate resistance
16000 ohm
ClassA; OperatingPoint1
Plate resistance
15000 ohm
ClassA; OperatingPoint2
Transconductance
8100 uS
ClassA; OperatingPoint1
Transconductance
9200 uS
ClassA; OperatingPoint2
Zero-signal plate current
32 mA
ClassA; OperatingPoint1
Zero-signal plate current
37 mA
ClassA; OperatingPoint2
Zero-signal grid 2 current
3.5 mA
ClassA; OperatingPoint1
Zero-signal grid 2 current
4 mA
ClassA; OperatingPoint2

Capacitance

Grid 1 to plate
0.5 pF
Direct interelectrode capacitance
Input capacitance
15 pF
Direct interelectrode capacitance
Output capacitance
9 pF
Direct interelectrode capacitance

Data set 02

1966 Tung Sol Electronic Tubes 3 of 4

Published operating points and test conditions from this source.

SECTION 1

Beam Power

Characteristic

Grid 1-to-plate capacitance
0.5 pF
WholeTube
Input capacitance
15 pF
WholeTube
Output capacitance
9 pF
WholeTube

Other

Maximum plate voltage
130 V
WholeTube
Maximum screen voltage
130 V
WholeTube
Maximum plate dissipation
5 W
WholeTube
Maximum screen dissipation
1.4 W
WholeTube
Plate resistance
16000 ohm
ClassA1
Transconductance
5200 µS
ClassA1