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Sounder 20ohms
A 20ohm sounder that is used on Morse circuits.
Mounted on a Mahogany base.
To be requisitioned separately:-
1 x Sounder-screen, Metal.
Specification - TG2004.
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Sounder 900ohms
A 900ohm sounder that is used on Morse circuits.
Mounted on a Mahogany base.
To be requisitioned separately:-
1 x Sounder-screen,
Metal.
Specification - TG2004.
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Sounder,
Double Plate
This was a set of two sounders, which were supplied
with a Galvanometer S.C. and a Sounder, Screen, Complete.
There were two types.
20ohm type includes:-
1 x Sounder,
Plate, B, 21ohm, Left.
1 x Sounder, Plate, B, 21ohm, Right.
2
x Shunts, Sounder, 420ohms.
900ohm type includes:-
1 x
Sounder, Plate, B, 1000ohm, Left.
1 x Sounder, Plate, B, 1000ohm,
Right.
2 x Shunts, Sounder, 9000ohms.
Diagram book Plate
37.
This is an alternative, and probably earlier form of the
double current system. 'The two plate sounders are
polarized and joined in parallel. In this way the instrument
becomes a directly worked one, with the relay and local battery
being dispensed with. A working current of 10mA is required. This
sounder has large horse-shoe polarizing magnets and the armatures
would be given a strong bias to hold the striker away from the
plate, and the magnet reversed in one relative to the other to allow
the sounders to respond to currents of opposite polarities.
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Sounder, Mechanical
These were used for training
purposes.
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Sounder, Plate
These was a set of two sounders that
would be fitted to a Sounder, Double, Plate. There were two
types.
20ohm type includes:-
1 x Sounder, Plate, B, 21ohm,
Left.
1 x Sounder, Plate, B, 21ohm, Right.
900ohm type
includes:-
1 x Sounder, Plate, B, 1000ohm, Left.
1 x Sounder,
Plate, B, 1000ohm, Right.
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Sounder,
Polarised, A
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Sounder,
Polarised, B
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Sounder,
Polarised, C
This is a four terminal, 200ohm +
200ohm, sounder used on D.C. circuits.
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Sounder,
Polarised, D
There are four types and each has a different coil resistance.
100+100ohms - 3 Terminal.
500+500ohms - 3 terminal
2000ohm
4500ohms
Drawing -
1812.
Specification - TG205 and TG2025.
The
polarized sounder is wound differentially. Using the two coil
500+500 type for example, the coil resistance can be
actuated with a current of 1/2mA; 3mA suffice for signals at the
rate of 20 words per minute, whilst with 10mA loud strong working
signals are produced.. The distance between the cores and the
armature when down should be 8 mils, and the play of the armature
should be 16 mils. When adjusted in this way the instrument can be
used with currents between 3 and 40mA without readjusting, and by
increasing the tension in the spring, much larger currents can be
used. The inductance is 62H.
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Sounder, Relaying
There are
four types and each has five terminals but a different coil
resistance.
30ohm - Used on repeaters with primary
cells.
40ohm - Used on Quad "B" side with primary cells.
500ohm -Used on repeaters with secondary cells.
900ohm - Used on
Quad "B" side with secondary cells.
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Sounder,
Vibrating No. 1
These were used as a night alarm sounder in trunk
exchanges (TL140) and consisted of two 10ohms coils in series.
Fitted with a brass cover.
Includes:-
1 x Condenser
0.08uf.
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Sounder, Vibrating No.
2
These were used on Fire Alarm systems (FA24) and
consisted of two 10ohms coils in series. Fitted with a brass
cover.
Drawing - 1253.
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