H
SECTION H — ELECTRICITY
 H03
BASIC ELECTRONIC CIRCUITRY
 H03F
AMPLIFIERS (measuring, testing G01R; masers, lasers H01S; coupling arrangements quite independent of the nature of the amplifier H03H; amplifiers capable only of dealing with pulses H03K)
 H03F

Note(s)

This sub-class deals with (a) linear amplification, there being linear relationship between the amplitudes of input and output, and the output having substantially the same waveform as the input, (b) dielectric amplifiers, magnetic amplifiers, and parametric amplifiers when used as oscillators or frequency-changers, and (c) constructions of active elements of dielectric amplifiers and parametric amplifiers for which no provision exists elsewhere.

 H03F 1/00
Details of amplifiers with only discharge tubes, or only semiconductor devices as amplifying elements
 H03F 1/02
·  Modifications of amplifiers to raise the efficiency, e.g. gliding Class A stages, use of an auxiliary oscillation
 H03F 1/04
·  ·  in discharge-tube amplifiers
 H03F 1/06
·  ·  ·  to raise the efficiency of amplifying modulated radio frequency waves, e.g. Doherty type; to raise the efficiency of amplifiers acting also as modulators
 H03F 1/08
·  Modifications of amplifiers to reduce influences of internal impedances of amplifying elements (wide-band amplifiers with inter-stage coupling networks incorporating these impedances H03F 1/42)
 H03F 1/10
·  ·  by use of amplifying elements with multiple electrode connections
 H03F 1/12
·  ·  by use of attenuating means
 H03F 1/14
·  ·  by use of neutralising means
 H03F 1/16
·  ·  ·  in discharge-tube amplifiers
 H03F 1/18
·  ·  by use of distributed coupling
 H03F 1/20
·  ·  ·  in discharge-tube amplifiers
 H03F 1/22
·  ·  by use of cascode coupling, i.e. earthed cathode or emitter stage followed by earthed grid or base stage respectively
 H03F 1/24
·  ·  ·  in discharge-tube amplifiers
 H03F 1/26
·  Modifications of amplifiers to reduce influence of noise generated by amplifying elements
 H03F 1/28
·  ·  in discharge-tube amplifiers
 H03F 1/30
·  Modifications of amplifiers to reduce influence of variations of temperature or supply voltage (by negative feedback H03F 1/34)
 H03F 1/32
·  Modifications of amplifiers to reduce non-linear distortion (by negative feedback H03F 1/34)
 H03F 1/34
·  Negative-feedback-circuit arrangements with or without positive feedback (H03F 3/50 takes precedence; for neutralisation purposes H03F 1/14)
 H03F 1/36
·  ·  in discharge-tube amplifiers
 H03F 1/38
·  Positive-feedback circuit arrangements without negative feedback
 H03F 1/40
·  ·  in discharge-tube amplifiers
 H03F 1/42
·  Modifications of amplifiers to extend the bandwidth
 H03F 1/44
·  ·  of tuned amplifiers
 H03F 1/46
·  ·  ·  with tubes only
 H03F 1/48
·  ·  of aperiodic amplifiers
 H03F 1/50
·  ·  ·  with tubes only
 H03F 3/00
Amplifiers with only discharge tubes or only semiconductor devices as amplifying elements
 H03F 3/02
·  with tubes only (subsequent sub-groups take precedence)
 H03F 3/04
·  with semiconductor devices only (subsequent sub-groups take precedence)
 H03F 3/06
·  ·  using hole storage effect
 H03F 3/08
·  ·  controlled by light
 H03F 3/10
·  ·  with diodes
 H03F 3/12
·  ·  ·  with Esaki diodes
 H03F 3/14
·  ·  with amplifying devices having more than three electrodes or more than two PN junctions
 H03F 3/16
·  ·  with field-effect devices
 H03F 3/18
·  with semiconductor devices of complementary types (subsequent sub-groups take precedence)
 H03F 3/20
·  Power amplifiers, e.g. Class B amplifier, Class C amplifier (H03F 3/26-H03F 3/32 take precedence)
 H03F 3/22
·  ·  with tubes only (H03F 3/24 takes precedence)
 H03F 3/24
·  ·  of transmitter output stages
 H03F 3/26
·  Push-pull amplifiers; Phase-splitters therefor (duplicated single-ended push-pull arrangements or phase-splitters therefor H03F 3/30)
 H03F 3/28
·  ·  with tubes only
 H03F 3/30
·  Single-ended push-pull amplifiers; Phase-splitters therefor
 H03F 3/32
·  ·  with tubes only
 H03F 3/34
·  Dc amplifiers in which all stages are dc-coupled
 H03F 3/36
·  ·  with tubes only
 H03F 3/38
·  Dc amplifiers with modulator at input and demodulator at output; Modulators or demodulators specially adapted for use in such amplifiers (modulators in general H03C; demodulators in general H03D)
 H03F 3/40
·  ·  with tubes only
 H03F 3/42
·  Amplifiers with two or more amplifying elements having their dc paths in series, the control electrode of each element being excited by at least part of the input signal, e.g. so-called totem-pole amplifiers
 H03F 3/44
·  ·  with tubes only
 H03F 3/46
·  Reflex amplifiers
 H03F 3/48
·  ·  with tubes only
 H03F 3/50
·  Amplifiers in which input is applied to, or output is derived from, an impedance common to input and output circuits of the amplifying element, e.g. cathode follower
 H03F 3/52
·  ·  with tubes only
 H03F 3/54
·  Amplifiers using transit-time effect in tubes
 H03F 3/56
·  ·  using klystrons
 H03F 3/58
·  ·  using travelling-wave tubes
 H03F 3/60
·  Amplifiers in which coupling networks have distributed constants, e.g. with waveguide resonators (H03F 3/54 takes precedence)
 H03F 3/62
·  Two-way amplifiers
 H03F 3/64
·  ·  with tubes only
 H03F 3/66
·  Amplifiers simultaneously generating oscillations of one frequency and amplifying signals of another frequency
 H03F 3/68
·  Combinations of amplifiers, e.g. multi-channel amplifiers for stereophonics
 H03F 5/00
Amplifiers with both discharge tubes and semiconductor devices as amplifying elements
 H03F 7/00
Parametric amplifiers
 H03F 7/02
·  using variable-inductance element; using variable-permeability element
 H03F 7/04
·  using variable-capacitance element; using variable-permittivity element
 H03F 7/06
·  with electron beam tube
 H03F 9/00
Magnetic amplifiers
 H03F 11/00
Dielectric amplifiers
 H03F 13/00
Amplifiers using amplifying element consisting of two mechanically- or acoustically-coupled transducers, e.g. telephone-microphone amplifier
 H03F 15/00
Amplifiers using galvano-magnetic effects not involving mechanical movement, e.g. using Hall effect
 H03F 17/00
Amplifiers using electroluminescent element or photocell
 H03F 19/00
Amplifiers using superconductivity effects
 H03F 21/00
Amplifiers not covered by groups H03F 3/00-H03F 19/00 (dynamo-electric amplifiers H02K)