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PL500

Sensibly equivalent to:
27GB5 PL504
See also:
PL500 - Line Output Valve
    
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The PL500 is a purpose designed television pentode line output valve (sweep tube). It was later replaced by the PL504.
The special feature of the PL500 was the introduction of the Cavitrap anode to reduce the ratio of screen grid to anode current. Although quoted as a pentode the construction is that of a beam tetrode.
The peak anode voltage is quoted as 7,000 Volts and shows why the line output stage of a television receiver was the last consumer electronics product to remain a valve. The CRT excepted of course.
TV line output valves found their way into amateur radio transmitters for service at HF (up to 30 MHz) because of their peak voltage characteristics and relatively high current capability.
The Control grid is wound on copper supports and has small heat sinks on the top of each copper rod. The screen grid is also wound on copper.
The beam plate within the anode. The image is looking along the grid axis.
The wide glass tube envelope is 28 mm in diameter and excluding the B9D base pins, is 95 mm tall.
References: Datasheet & 1040. Type PL500 was first introduced in 1961.

 

Pin Connections
B9D
1
2
3
4
5
6
7
8
9
tc
g1
g1
k,g3
h
h
g2
g2
k,g3
k
a

 

Absolute Maximum Operating Conditions
Pentode
Vh
Ah
Va
Vs
mAa
mAs
Pdiss
27
0.3
230
200
100
10
12W
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated August 20, 2019.
shape:wide.glass.tube construction:all.glass type:pentode age:1960.1975 base:b9d heater:300ma pins:9 pin:1.g1 pin:2.g1 pin:3.k.g3 pin:4.h pin:5.h pin:6.g2 pin:7.g2 pin:8.k.g3 pin:9.k pin:tc.a
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