H
SECTION H — ELECTRICITY
 H03
BASIC ELECTRONIC CIRCUITRY
 H03K
PULSE TECHNIQUE (measuring pulse characteristics G01R; mechanical counters having an electrical input G06M; storage devices G11; construction of switches involving contact making and breaking for generation of pulses, e.g. by using a moving magnet, H01H; generators of substantially sinusoidal oscillations H03B; modulating sinusoidal oscillations with pulses H03C, H04L; discriminator circuits involving pulse counting H03D)
 H03K

Note(s)

  1. This sub-class deals with (a) methods, circuits, devices, or apparatus for generating, counting, amplifying, shaping, modulating, demodulating, coding, decoding, or otherwise manipulating substantially non-sinusoidal oscillations, i.e. electric pulses, (b) electronic switching not involving contact-making and breaking, and (c) logic circuits handling electric pulses.
  2. In this sub-class: An "active element" is understood to exercise control over the conversion of input energy into an oscillation or a discontinuous flow of energy.
 H03K 1/00
Details of generators (modifications of specific types of generators H03K 3/00, H03K 4/00)
 H03K 1/02
·  Modifications of generator to compensate for variations of physical values, e.g. power supply, load
 H03K 1/04
·  ·  for variations in temperature alone
 H03K 1/06
·  Modifications of generator to ensure starting of oscillations
 H03K 1/08
·  Modifications of generator to maintain constant energy content with change of pulse repetition rate
 H03K 1/10
·  Modificaion of generator to prevent operation by noise or inteference
 H03K 1/12
·  Regulation of generator output (by modification of generator H03K 1/02)
 H03K 1/14
·  ·  of amplitude
 H03K 1/16
·  ·  of frequency or repetition rate
 H03K 1/18
·  ·  of width; of duty cycle
 H03K 3/00
Generating electric pulses (H03K 4/00 takes precedence; by distortion of other wave forms H03K 5/00)
 H03K 3/02
·  Generators characterised by the type of circuit or other means used for producing pulses (H03K 3/64-H03K 3/82 take precedence)
 H03K 3/04
·  ·  using as active elements vacuum tubes only, with positive feedback
 H03K 3/05
·  ·  ·  using means other than a transformer for feedback
 H03K 3/06
·  ·  ·  ·  using at least two tubes so coupled that the input of one is derived from the output of another, e.g. multivibrator
 H03K 3/08
·  ·  ·  ·  ·  astable
 H03K 3/10
·  ·  ·  ·  ·  mono-stable
 H03K 3/12
·  ·  ·  ·  ·  bi-stable
 H03K 3/14
·  ·  ·  ·  ·  multi-stable
 H03K 3/15
·  ·  ·  ·  ·  Circuits of which the state is dependent on the level of the input signal, e.g. Schmitt trigger
 H03K 3/16
·  ·  ·  using a transformer for feedback, e.g. blocking oscillator with saturable core
 H03K 3/22
·  ·  ·  ·  specially adapted for amplitude comparison, i.e. Multiar
 H03K 3/26
·  ·  using as active elements transistors with internal or external positive feedback
 H03K 3/28
·  ·  ·  using means other than a transformer for feedback
 H03K 3/281
·  ·  ·  ·  using at least two transistors so coupled that the input of one is derived from the output of another, e.g. multivibrator
 H03K 3/282
·  ·  ·  ·  ·  astable
 H03K 3/284
·  ·  ·  ·  ·  mono-stable
 H03K 3/286
·  ·  ·  ·  ·  bi-stable
 H03K 3/29
·  ·  ·  ·  ·  multi-stable
 H03K 3/295
·  ·  ·  ·  ·  Circuits of which the state is dependent on the level of the input signal, e.g. Schmitt trigger
 H03K 3/30
·  ·  ·  using a transformer for feedback, e.g. blocking oscillator
 H03K 3/31
·  ·  using as active elements semiconductor devices with two electrodes and exhibiting negative resistance characteristic
 H03K 3/315
·  ·  ·  using tunnel diodes
 H03K 3/33
·  ·  using as active elements semiconductor devices exhibiting hole storage or enhancement effect
 H03K 3/335
·  ·  using as active elements semiconductor devices with more than two electrodes and exhibiting avalanche effect
 H03K 3/35
·  ·  using as active elements semiconductor devices with more than two PN junctions, or more than three electrodes, or more than one electrode in the same conductivity region
 H03K 3/37
·  ·  using gas-filled tubes as active elements, e.g. astable trigger circuits (H03K 3/55 takes precedence)
 H03K 3/38
·  ·  using cryotrons as active elements
 H03K 3/40
·  ·  using electrochemical cells as active elements
 H03K 3/42
·  ·  using electro-optical devices as active elements to produce electric pulses
 H03K 3/43
·  ·  using beam deflection tubes as active elements
 H03K 3/45
·  ·  using as active elements non-linear magnetic devices; using as active elements non-linear dielectric devices
 H03K 3/47
·  ·  ·  using parametrons
 H03K 3/49
·  ·  ·  using ferro-resonant devices
 H03K 3/51
·  ·  ·  using multi-aperture magnetic cores, e.g. transfluxor
 H03K 3/53
·  ·  using an energy-accumulating element discharged through the load by a switching device controlled by an external signal and not incorporating positive feedback (H03K 3/335 takes precedence)
 H03K 3/55
·  ·  ·  using gas-filled tubes having a control electrode
 H03K 3/57
·  ·  ·  using semiconductor devices
 H03K 3/64
·  Generators producing trains of pulses, i.e. finite sequences of pulses
 H03K 3/66
·  ·  by interrupting the output of a generator
 H03K 3/70
·  ·  ·  time intervals between all adjacent pulses of one train being equal
 H03K 3/72
·  ·  with means for varying repetition rate of trains
 H03K 3/78
·  Generating a single train of pulses having a predetermined pattern, e.g. a predetermined number
 H03K 3/80
·  Generating trains of sinusoidal oscillations (by interrupting H03C, H04L)
 H03K 3/82
·  Generating pulses at random intervals
 H03K 4/00
Generating pulses having essentially a finite slope or stepped portions (by distorting other waveforms H03K 6/00)
 H03K 4/02
·  having stepped portions, e.g. staircase waveform
 H03K 4/04
·  having parabolic shape
 H03K 4/06
·  having triangular shape
 H03K 4/08
·  ·  having sawtooth shape
 H03K 4/10
·  ·  ·  using as active elements vacuum tubes only
 H03K 4/12
·  ·  ·  ·  in which a sawtooth voltage is produced across a capacitor
 H03K 4/14
·  ·  ·  ·  ·  using two tubes so coupled that the input of each one is derived from the output of the other, e.g. multivibrator
 H03K 4/16
·  ·  ·  ·  ·  using a single tube with positive feedback through transformer, e.g. blocking oscillator
 H03K 4/18
·  ·  ·  ·  ·  using a single tube exhibiting negative resistance between two of its electrodes, e.g. transitron, dynatron
 H03K 4/20
·  ·  ·  ·  ·  using a tube with negative feedback by capacitor, e.g. Miller integrator
 H03K 4/22
·  ·  ·  ·  ·  ·  combined with transitron, e.g. phantastron, sanatron
 H03K 4/24
·  ·  ·  ·  ·  Boot-strap generators
 H03K 4/26
·  ·  ·  ·  in which a sawtooth current is produced through an inductor
 H03K 4/28
·  ·  ·  ·  ·  using an amplifier operating as a switching device and driven only by substantially rectangular voltage pulses
 H03K 4/30
·  ·  ·  ·  ·  ·  using a tube with negative feedback through a capacitor, el g. Miller integrator
 H03K 4/32
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/34
·  ·  ·  ·  ·  ·  ·  using a single tube with positive feedback through a transformer
 H03K 4/36
·  ·  ·  ·  ·  ·  ·  using a single tube exhibiting negative resistance between two of its electrodes, e.g. transitron, dynatron
 H03K 4/38
·  ·  ·  ·  ·  ·  ·  ·  combined with Miller integrator
 H03K 4/40
·  ·  ·  ·  ·  using an amplifier driven only by substantially sawtooth voltage pulses
 H03K 4/42
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/44
·  ·  ·  ·  ·  using an amplifier driven by a combination of sawtooth and rectangular voltage pulses
 H03K 4/46
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/48
·  ·  ·  using as active elements semiconductor devices (H03K 4/78-H03K 4/84 take precedence)
 H03K 4/50
·  ·  ·  ·  in which a sawtooth voltage is produced across a capacitor
 H03K 4/52
·  ·  ·  ·  ·  using two semiconductor devices so coupled that the input of each one is derived from the output of the other, e.g. multivibrator
 H03K 4/54
·  ·  ·  ·  ·  using a single semiconductor device with positive feedback through a transformer, e.g. blocking oscillator
 H03K 4/56
·  ·  ·  ·  ·  using a semiconductor device with negative feedback through a capacitor, e.g. Miller integrator
 H03K 4/58
·  ·  ·  ·  ·  Boot-strap generators
 H03K 4/60
·  ·  ·  ·  in which a sawtooth current is produced through an inductor
 H03K 4/62
·  ·  ·  ·  ·  using amplifier operating as a switching device and driven by substantially rectangular pulses only
 H03K 4/64
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/66
·  ·  ·  ·  ·  ·  ·  using a single device with positive feedback, e.g. blocking oscillator
 H03K 4/68
·  ·  ·  ·  ·  ·  Generators in which the switching device is conducting during the fly-back part of the cycle
 H03K 4/70
·  ·  ·  ·  ·  using an amplifier driven substantially sawtooth pulses only
 H03K 4/72
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/74
·  ·  ·  ·  ·  using an amplifier driven by a combination of sawtooth and rectangular pulses
 H03K 4/76
·  ·  ·  ·  ·  ·  combined with means for generating the driving pulses
 H03K 4/78
·  ·  ·  using as active elements tunnel diodes
 H03K 4/80
·  ·  ·  using as active elements multi-layer diodes
 H03K 4/82
·  ·  ·  using as active elements semiconductor more than three electrodes
 H03K 4/84
·  ·  ·  ·  Generators in which the semiconductor device is conducting during the fly-back part of the cycle
 H03K 4/86
·  ·  ·  using as active elements gas-filled tubes
 H03K 4/88
·  ·  ·  using as active elements electrochemical cells
 H03K 5/00
Manipulating pulses not covered by one of the other main groups in this sub-class (circuits with regenerative action H03K 3/00, H03K 4/00; using non-linear magnetic or dielectric devices H03K 3/45)
 H03K 5/01
·  Shaping pulses
 H03K 5/02
·  ·  by amplifying (H03K 5/04 takes precedence; wide-band amplifiers in general H03F)
 H03K 5/04
·  ·  by increasing duration; by decreasing duration
 H03K 5/08
·  ·  by limiting, by thresholding, by slicing, i.e. combined limiting and thresholding (by comparing one pulse with another H03K 5/20)
 H03K 5/12
·  ·  by steepening leading or trailing edges
 H03K 5/13
·  Arrangements having a single output and transforming input signals into pulses delivered at desired time intervals
 H03K 5/153
·  Arrangements in which a pulse is delivered at the instant when a predetermined characteristic of an input signal is present or at a fixed time interval after this instant
 H03K 5/156
·  Arrangements in which a continuous pulse train is transformed into a train having a desired pattern
 H03K 5/159
·  Applications of delay lines not covered by the foregoing sub-groups
 H03K 5/18
·  Monitoring individual pulses; Monitoring pulse trains; Monitoring selected pulses therein
 H03K 5/20
·  Comparing one pulse with another pulse; Sorting pulses, e.g. according to amplitude
 H03K 6/00
Manipulating pulses having a finite slope and not covered by one of the other main groups of this sub-class (circuits with regenerative action H03K 4/00)
 H03K 6/02
·  Amplifying pulses
 H03K 6/04
·  Modifying slopes of pulses
 H03K 6/06
·  Producing pulses by distortion of sinusoidal waveforms
 H03K 7/00
Modulating pulses with a continuously-variable modulating signal
 H03K 7/02
·  Amplitude modulation, i.e. PAM
 H03K 7/04
·  Position modulation, i.e. PPM
 H03K 7/06
·  Frequency or rate modulation, i.e. PFM or PRM
 H03K 7/08
·  Duration or width modulation
 H03K 7/10
·  Combined modulation, e.g. rate modulation and amplitude modulation
 H03K 9/00
Demodulating pulses which have been modulated with a continuously-variable signal
 H03K 9/02
·  of amplitude-modulated pulses
 H03K 9/04
·  of position-modulated pulses
 H03K 9/06
·  of frequency- or rate-modulated
 H03K 9/08
·  of duration- or width-modulated
 H03K 9/10
·  of pulses having combined modulation
 H03K 11/00
Transforming types of modulation, e.g. position-modulated pulses into duration-modulated pulses
 H03K 13/00
Coding; Decoding
 H03K 13/02
·  Analogue/digital conversion; Digital/analogue conversion
 H03K 13/04
·  ·  by adding selected weighted values
 H03K 13/06
·  ·  ·  using successive addition or subtraction and repeated comparison with predetermined amplitudes
 H03K 13/07
·  ·  ·  ·  with magnetic flux storage
 H03K 13/10
·  ·  ·  ·  with charge storage (H03K 13/14, H03K 13/16 takes precedence)
 H03K 13/12
·  ·  ·  ·  ·  Supplying successive charges of different duration or amplitude
 H03K 13/14
·  ·  ·  ·  by using stepped impedance
 H03K 13/16
·  ·  ·  by using different decay times of charges initially produced; by using exponentially varying voltages
 H03K 13/17
·  ·  in which several reference values of different magnitudes are compared with the analogue value in succession, i.e. iterative type
 H03K 13/175
·  ·  in which several reference values are compared simultaneously with the analogue value, i.e. direct comparing type
 H03K 13/18
·  ·  by direct conversion, i.e. by reading a selected entry from a conversion device, e.g. coded tube
 H03K 13/20
·  ·  by intermediate conversion to a duration or frequency and subsequent counting
 H03K 13/22
·  Delta modulation; Differential modulation
 H03K 13/24
·  Converting from one code into another code
 H03K 13/243
·  ·  Static code converters in which one or more input lines are connected to one or more output lines, e.g. matrix type
 H03K 13/247
·  ·  ·  using magnetic elements, e.g. transfluxors
 H03K 13/25
·  ·  ·  using semiconductor devices (H03K 13/252 takes precedence)
 H03K 13/252
·  ·  ·  using diodes
 H03K 13/254
·  ·  ·  using resistive or capacitive elements
 H03K 13/256
·  ·  Dynamic code converters, in which a succession of pulses in one line is converted into several simultaneously occurring pulses in several parallel lines or vice versa, e.g. series /parallel converter
 H03K 13/258
·  ·  ·  using shift registers (shift registers per se G11C)
 H03K 13/32
·  Error detection; Error correction; Monitoring
 H03K 13/34
·  ·  Ensuring error-free coding or decoding, e.g. using parity check
 H03K 17/00
Electronic switching or gating, i.e. not by contact-making and -breaking
 H03K 17/02
·  Details (modifications of specific types H03K 17/52-H03K 17/88)
 H03K 17/04
·  ·  Modifications for accelerating switching
 H03K 17/06
·  ·  Modifications for ensuring a fully conducting state
 H03K 17/08
·  ·  Modifications for protecting switching circuit against overload
 H03K 17/10
·  ·  Modifications for increasing the maximum permissible switched voltage
 H03K 17/12
·  ·  Modifications for increasing the maximum permissible switched current
 H03K 17/14
·  ·  Compensating for effects of temperature changes
 H03K 17/16
·  ·  Modifications for eliminating interference voltages or currents
 H03K 17/18
·  ·  Modifications for indicating state of switch
 H03K 17/20
·  ·  Modifications for resetting core switching units to a predetermined state
 H03K 17/22
·  ·  Modifications for ensuring a predetermined initial state when the supply voltage has been applied (bi-stable generators H03K 3/12)
 H03K 17/24
·  ·  ·  Storing the actual state when the supply voltage fails
 H03K 17/26
·  ·  Modifications for temporary blocking after receipt of control pulses
 H03K 17/28
·  ·  Modifications for introducing a time delay before switching
 H03K 17/30
·  ·  Modifications for providing a predetermined threshold before switching
 H03K 17/52
·  using gas-filled tubes
 H03K 17/54
·  using vacuum tubes (diodes H03K 17/74)
 H03K 17/56
·  using semiconductor devices (diodes H03K 17/74)
 H03K 17/58
·  ·  using tunnel diodes
 H03K 17/60
·  ·  using transistors
 H03K 17/62
·  ·  ·  Distributing arrangements (code converters H03K 13/24)
 H03K 17/64
·  ·  ·  having inductive loads
 H03K 17/66
·  ·  ·  Switching arrangements for passing the current in either direction at will; Switching arrangements for reversing the current at will
 H03K 17/68
·  ·  ·  specially adapted for switching ac currents or voltages
 H03K 17/70
·  ·  having two electrodes and exhibiting negative resistance (using tunnel diodes H03K 17/58)
 H03K 17/72
·  ·  having more than two PN junctions; having more than three electrodes; having more than one electrode at the same conductivity region
 H03K 17/74
·  using diodes
 H03K 17/76
·  ·  Distributing arrangements (code converters H03K 13/24)
 H03K 17/78
·  using electro-optical devices
 H03K 17/80
·  using non-linear magnetic devices; using non-linear dielectric devices
 H03K 17/82
·  ·  using transfluxors
 H03K 17/84
·  ·  using thin-film devices
 H03K 17/86
·  ·  using twistors
 H03K 17/88
·  using beam-deflection tubes
 H03K 19/00
Logic circuits, i.e. having at least two inputs acting on one output; Inverting circuits
 H03K 19/02
·  characterised by the components used
 H03K 19/04
·  ·  using gas-filled tubes
 H03K 19/06
·  ·  using vacuum tubes (using diode rectifiers H03K 19/12)
 H03K 19/08
·  ·  using semiconductor devices (using tunnel diodes H03K 19/10; using diode rectifiers H03K 19/12)
 H03K 19/10
·  ·  using tunnel diodes
 H03K 19/12
·  ·  using diode rectifiers
 H03K 19/14
·  ·  using electro-optical devices
 H03K 19/16
·  ·  using saturable magnetic devices
 H03K 19/162
·  ·  ·  using parametrons
 H03K 19/164
·  ·  ·  using ferro-resonant devices
 H03K 19/166
·  ·  ·  using transfluxors
 H03K 19/168
·  ·  ·  using thin-film devices
 H03K 19/17
·  ·  using twistors
 H03K 19/20
·  characterised by logic function (H03K 19/02 takes precedence)
 H03K 19/22
·  ·  AND circuits, i.e. giving output if all inputs exist
 H03K 19/24
·  ·  ·  Coincidence circuits, i.e. giving output if trigger criterion exists simultaneously at all inputs
 H03K 19/26
·  ·  ·  Amplitude coincidence circuits, i.e. giving output only if all inputs are of equal amplitude (amplitude comparators H03K 3/22)
 H03K 19/28
·  ·  ·  Coincidence circuits with at least one trigger criterion of polarity opposite to the other criteria
 H03K 19/30
·  ·  OR circuits, i.e. giving output if trigger criterion exists at least at one input
 H03K 19/32
·  ·  EXCLUSIVE OR circuits, i.e. giving output if trigger criterion exists at only one input
 H03K 19/34
·  ·  NOR circuits, i.e. giving no output if trigger criterion exists at least at one input
 H03K 19/36
·  ·  NAND circuits, i.e. giving no output if trigger criterion exists at all inputs
 H03K 19/38
·  ·  BUT NOT circuits, i.e. giving output if trigger criterion exists at least at one input and no inhibiting criterion exists at a predetermined further input
 H03K 19/40
·  ·  NOT or inverting circuits, i.e. giving no output if input exists
 H03K 19/42
·  ·  Majority circuits, i.e. giving output having the state of the majority of the inputs
 H03K 19/44
·  ·  Minority circuits, i.e. giving output having the state of the minority of the inputs
 H03K 21/00
Details of pulse counters of frequency dividers
 H03K 21/02
·  Input circuits for pulses
 H03K 21/04
·  ·  comprising pulse-shaping or -differentiating circuits
 H03K 21/06
·  ·  comprising logic circuits
 H03K 21/08
·  Output circuits for pulses
 H03K 21/10
·  ·  comprising logic circuits
 H03K 21/12
·  ·  ·  with parallel read-out
 H03K 21/14
·  ·  ·  with series read-out of number stored
 H03K 21/16
·  Circuits for carrying-over pulses between successive decades
 H03K 21/18
·  Circuits for indicating the result
 H03K 21/20
·  ·  using glow-discharge lamps
 H03K 21/22
·  ·  ·  using multi-cathode lamps
 H03K 21/24
·  ·  using incandescent lamps
 H03K 21/26
·  ·  using pointer meters, e.g. electrometers
 H03K 21/28
·  ·  using amplifying devices
 H03K 21/30
·  Circuits for starting, stopping, or monitoring the counter
 H03K 21/32
·  ·  Starting-circuits; Resetting-circuits
 H03K 21/34
·  ·  Monitoring-circuits
 H03K 21/36
·  ·  for predetermined counting, i.e. counters which can be set to a predetermined starting condition or which produce an output signal when a predetermined number of pulses has been received
 H03K 23/00
Pulse counters comprising counting chains; Frequency dividers comprising counting chains (H03K 29/00 takes precedence)
 H03K 23/02
·  comprising a chain of identical two-state stages which are successively brought from one state into the other by successive pulses, these being applied simultaneously to more than one stage, e.g. ring counter
 H03K 23/03
·  ·  using relays
 H03K 23/035
·  ·  ·  using two groups of relays, e.g. one for odd- and one for even-digit positions
 H03K 23/04
·  ·  using bi-stable regenerative trigger circuits
 H03K 23/06
·  ·  ·  in which the active elements are only vacuum tubes
 H03K 23/08
·  ·  ·  in which the active elements are only semiconductor devices having at least three electrodes
 H03K 23/10
·  ·  using bi-stable magnetic cores; using bi-stable ferro-electric capacitors
 H03K 23/12
·  ·  using bi-stable electro-optical devices
 H03K 23/14
·  ·  using semiconductor devices having only two electrodes, e.g. Zener diode; using thermistors
 H03K 23/16
·  ·  ·  with negative resistance characteristics, e.g. tunnel diode, multi-layer diode
 H03K 23/18
·  ·  using gas-filled tubes
 H03K 23/20
·  ·  using vacuum tubes (H03K 23/06 takes precedence)
 H03K 23/22
·  ·  using semiconductor devices having at least three electrodes (H03K 23/08 takes precedence)
 H03K 23/24
·  comprising a chain of bi-stable stages, the pulses being applied to one stage only
 H03K 23/25
·  ·  using relays
 H03K 23/255
·  ·  ·  using two groups of relays, e.g. one for odd- and one for even-digit positions
 H03K 23/26
·  ·  using bi-stable regenerative trigger circuits
 H03K 23/28
·  ·  ·  in which the active elements are only vacuum tubes
 H03K 23/30
·  ·  ·  in which the active elements are only semiconductor devices having at least three electrodes
 H03K 23/32
·  ·  using bi-stable magnetic cores; using bi-stable ferro-electric capacitors
 H03K 23/34
·  ·  using bi-stable electro-optical devices
 H03K 23/36
·  ·  using semiconductor devices having only two electrodes, e.g. tunnel diode, multi-layer diode
 H03K 23/38
·  ·  using gas-filled tubes
 H03K 25/00
Pulse counters with step-by-step integration and static storage; Analogous frequency dividers
 H03K 25/02
·  comprising charge storage, e.g. capacitor without polarisation hysteresis
 H03K 25/04
·  ·  using auxiliary pulse generator triggered by the incoming pulses (H03K 25/10 takes precedence)
 H03K 25/06
·  ·  ·  with mono-stable multivibrator
 H03K 25/08
·  ·  ·  with blocking oscillator
 H03K 25/10
·  ·  using feedback for linearisation of successive charges
 H03K 25/12
·  comprising hysteresis storage
 H03K 25/14
·  ·  using ferro-electric capacitor
 H03K 25/16
·  ·  ·  with feedback for linearisation of successive charges
 H03K 25/18
·  ·  using ferromagnetic inductor
 H03K 27/00
Pulse counters in which pulses are continuously circulated in a closed loop; Analogous frequency dividers
 H03K 27/02
·  comprising a delay line in the closed loop
 H03K 29/00
Pulse counters comprising multi-stable elements, e.g. for ternary scale, for decimal scale; Analogous frequency dividers
 H03K 29/02
·  comprising multi-cathode gas-discharge tubes, electron-beam switching tubes or analogous semiconductor switching devices