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AC/SG

Sensibly equivalent to:
8A1 AC/S2Pen CV1164 CV2822 HP4101C MS/Pen MSP4 SP4 SPT4A
See also:
Mazda 1929 Valve Range Advert - Mazda AC Valves advert - Mazda Brand advert - Some Important British Valves
    
Extras ▼

 

The Mazda AC/SG is and AC heated Screen Grid or tetrode amplifier for RF use. Our other AC/SG has a different construction and shows how the box screen moved to a helical grid.
The heater is the then UK standard of 4.0 Volts at 1.0 Amp. The original valves in 1929 had a metal screw top cap as can be seen in the advert. The screw top cap style of this exhibit is difficult to determine as it is missing. The lack of adhesive residue is a possible indication that this originally had the metal screw top cap connection. However, the balloon envelope does not have the lower cylindrical section that appears in both the advert and AC/SG. It is possible that the bulb shape altered before the top cap was replaced with the Bakelite screw top version.
See also the metalised AC/SG.
The construction has a bright anode either side of a rectangular screening cage. This view is looking directly at one anode. The thick wires either side are supports that are connected to the screen. The two anode plates are bridged together and connect to the top cap wire.
This image was taken looking at the corner of the screening box. The control grid is hard to see as the wires have a very similar pitch to the screen.
A closer view.
The balloon envelope is 45 mm in diameter, and excluding the B5 base pins is 104 mm tall.
References: 1040 & 1043. Type AC/SG was first introduced in 1929.

 

Pin Connections
B5
1
2
3
4
5
tc
g2
g1
h
h
k
a

 

Absolute Maximum Operating Conditions
Tetrode
Vh
Ah
Va
Vs
Vg
mAa
mAs
ra
gm
4.0
1.0
200
60
-1.5
4.5
0.8
0.9M
1.9
Updated November 21, 2016.
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