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SP181

 
See also:
Ediswan Advert, December 1948 - The Famous EF50 of WWII
    
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The SP181 is an RF pentode designed to operate within equipment with a 200 mA heater chain. The operating frequency quoted is 45 MHz which is the frequency of operation of the Pye IF strip used in war time radar receivers. It also fits with Band I television. The introduction date of 1940 suggest it was initially designed for pre-war television receivers. It has a straight characteristic rather than variable μ and pre-war vision receivers were normally of the TRF (Tuned Radio Frequency) type where AGC was not applied.
The reverse is plain zinc paint.
The classic envelope is 32 mm in diameter, and excluding the MO base pins is 80 mm tall.
References: Datasheet, 1040 & 1043. Type SP181 was first introduced in 1940.

 

Pin Connections
MO
1
2
3
4
5
6
7
8
tc
h
k
a
g2
g3
m
-
h
g1

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
Vg
mAa
mAs
gm
18
0.2
250
250
-
10.9
2.7
8.5
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated March 17, 2014.
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