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QQZ03-20

Sensibly equivalent to:
YL1020
    
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The QQZ03-20 from Mullard is the quick heating form of the QQV03-20A double beam transmitting tetrode.
Following the European pattern, a central flat cathode is surrounded by a split control grid (one half per valve), a common screen grid is wound next. The two beam forming plates can be seen either side of the central assembly. The anodes are finned for good heat dissipation and clearly separated from the central structures, the anodes are brought out to pin like top caps.
The heater runs at 1.6 Volts and 4.25 Amps. The surge at power-up is sufficient to raise the cathode to an operating temperature such that 70% of rated output is available in 0.7 Seconds. Note that the pins are connected to the electrodes with copper straps, probably because of the surge of power on transmit.
In addition to use as transmitter power amplifiers the upper frequency of 600 MHz made them popular for frequency multiplication.
See also QQV03-20.
The wide glass tube envelope is 44 mm in diameter and, excluding the B7A base pins and top pins is 53 mm tall.
Reference: Datasheet. Type QQZ03-20 was first introduced in 1964.

 

Pin Connections
B7A
1
2
3
4
5
6
7
tc
tc
f(2)
g1(2)
g2
f(1),bp,s
ic
g1(1)
f(2)
a(2)
a(1)

 

Absolute Maximum Operating Conditions
Tetrode
Vh
Ah
Va
Vs
Vg
mAa
mAs
mAg
Pdriv
Pout
Pdiss
freq
f.max
1.6
4.25
600
250
-60
100
8
1.4
1.5W
48
20W
200
600
Thanks to Frank Philipse for supplying the above PDF datasheet.
Updated February 08, 2013.
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