valve, tube, thermionic, electron, triode, tetrode, pentode, power,
magic eye, tuning indicator, nixie, history, data, data sheet,
specification, amplifier, radio, octal, B9A, B7G, B4, IO, KT88,
KT66, 12AX7, 12AY7, 12AT7, ECC81, ECC82, ECC83, 6L6, 6V6, EL34,
EL84, EM34, EM80, EM81, EM85, Mullard, Cossor, GEC, Gold Lion,
Marconi, Svetlana, Brimar, Ferranti, RCA, Sylvania, GE,6202,
amperex, arcturus, brimar, channelmaster, colvern, cossor dario,
debanks, edicron, ediswan, ei, elpico, emi emston, era, eratron,
ever-ready, ferranti, ge, gec heinz, kaufman, haltron, hivac, hrs,
itt, jackson lamba, lorenz, marconi, mazda, mullard, national,
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standard, svetlana, sylvania, telefunken, tronix, tungsram united,
valvo, westinghouse, zaerix
The "Shire Three" Interstage Transformers
Interstage transformers were very often used
between LF stages in early battery sets. Commonly they were of 3:1
or 5:1 step up ratio. This voltage magnification was an important
source of gain. It depends on the ratio of the source to driven
impedances being significantly greater than the inverse square of
the voltage gain. The high impedance of the grid circuit of a valve
is essential. This coupling method is the primary reason for the
low anode impedances designed into most battery triodes used as
detectors and LF stages before the output.
