Radio Valve Data: 1915-1960

Keith R Thrower OBE, The Valve Museum, April, 2022.

Triode Receiver Valves (pre-1926)^*

Type or
Trademark

Filament

Anode

Grid

r_a

g_m

μ

Year

Base

Notes
and applications

^{(1)The letters indicate the three types of filaments found on these valves. B = bright emitter, D = dull emitter, O = oxide-coated.}

Volts

Amps

Volts

-Volts

kΩ

mA/V

^{(2)The year shown is when it is believed the type was first issued. This date is accurate for most types but cannot be guaranteed for them all.}

^{(3)Pin-out details for non-exhibits can be found with the base details.}

  ^{★This table lists valves that were manufactured in the UK or which were claimed to be of UK manufacture. In practice several of the smaller companies imported their valves from abroad.}

 Thorpe

K.1

B

5.0

0.36

30-80

40.0

0.20

8.0

1924

B4

General purpose

Four-electrode Valves (Bi-grid)

Type or
Trademark

Filament

Anode ^{(8)The anode and inner grid were usually supplied with the same voltage.}

Outer Grid ^{(9)The outer grid is equivalent to the control grid of the triode valve.}

r_a

g_m

μ

Year

Base

Notes
and applications

^{(1)The letters indicate the three types of filaments found on these valves. B = bright emitter, D = dull emitter, O = oxide-coated.}

Volts

Amps

Volts

-Volts

kΩ

mA/V

^{(2)The year shown is when it is believed the type was first issued. This date is accurate for most types but cannot be guaranteed for them all.}

^{(3)Pin-out details for non-exhibits can be found with the base details.}

 Thorpe

K.4

B

4-6

0.5

0

1924

T5

All three types were

U.C.4

B

5.0

0.65

0

1925

B4 + st

mainly used in

U.C.5

B

5.0

0.65

0

1925

T5

Unidyne receivers.