LESSON TWENTY-TWO. DETECTORS.The little bobbins of the telephone receivers exert a very powerful choking action upon the currents of high frequency which effectually blocks their passage and prevents them from having any action upon the receiver.The purpose of the detector is to change these currents into such as will flow readily through the magnets of the telephone receiver and manifest themselves as sounds recognizable from their duration and periodicity as signals of the telegraph code.FIG. 45. Electrolytic Detector.FIG. 45. Electrolytic Detector.Probably the most well known form is the electrolytic detector which consists of an exceedingly fine platinum wire dipping into a cup of dilute nitric acid far enough to just touch the surface of the liquid. The telephone receivers are connected to the detector, in series with a battery. The current from the detector causes bubbles to continuously form on the end of the wire and insulate it from the liquid so that the current cannot flow. When the aerial is struck by a wave, the feeble alternating currents break down the bubbles and permit the currents to flow, causing a sound in the telephone receivers.The detectors in most common use to-day are of the crystal or rectifying type. There are a great many different forms of this type of detector, each one of which possesses certain features making it peculiarly adaptable under certain circumstances.FIG. 46. Silicon Detector.FIG. 46. Silicon Detector.The silicon detector consists of a flat surface of highly polished silicon upon which rests a brass point.The Pyron detector is composed of a crystal of iron pyrites embedded in a cup of fusible metal. A small wire spring bears against the surface of the crystal. The Pyron detector is somewhat harder to adjust than other forms of crystal detector, but remains in a sensitive condition much longer.FIG. 47. Perikon Detector.FIG. 47. Perikon Detector.The Perikon detector consists of a cup of fusible alloy in which are imbedded several pieces of a mineral called zincite. Another cup containing a fragment of chalcopyrites or bornite is held in a cup carried on the end of a rotating rod. The chalcopyrites is brought into contact with one of the crystals of zincite and the pressure adjusted by means of a spring. The Perikon detector will operate without a battery, but that latter is necessary in order to obtain the best results when receiving faint or far away signals.FIG. 48. Galena Detector.FIG. 48. Galena Detector.The Perikon Electra detector is a very sensitive form of the regular Perikon detector fitted with a micrometer adjustment.The Galena detector consists of a crystal of that material to which contact is made by means of a fine wire spring exerting very light pressure.FIG. 49. Audion Detector.FIG. 49. Audion Detector.Crystal detectors act as rectifiers and change the alternating currents Into direct currents, which will pass through the telephone receivers. Minerals used for this purpose are said to possessunilateral conductivity, that is, they conduct currents better in one direction than the other and act much the same as a valve which allows water to flow in one direction, but not in the other.Another well known detector of the "valve" type is that known as theAudion, consisting of a small incandescent lamp containing a small grid and plate of nickel. When the lamp is lighted by connecting a battery to the filament, a flow of ions passing from the hot filament through the grid to the plate is set up. The grid and plate form part of the receiving circuit containing the telephones. The flow of ions carries the oscillatory currents from the grid to the plate, but does not allow them to pass back again. In this manner, the alternating oscillatory currents are converted into direct currents, which will pass through the telephone receivers.FIG. 50. Carborundum Detector.FIG. 50. Carborundum Detector.The Carborundum detector, as its name implies, is a device making use of theunilateral conductivityof carborundum. This form of detector is very sensitive and has been employed for a number of years in all the installations of the United Wireless Telegraph Co.It consists of a small crystal of carborundum clamped tightly between two carbon electrodes. It may be used with or without a battery. The battery is preferred.The Magnetic detector is a very sensitive device utilizing the changes in the magnetic state of iron, which are caused by rapidly oscillating currents. If a core of iron wires be placed in a varying magnetic field, the magnetization of the iron will lag behind the magnetizing force on account ofhysteresisor "magnetic friction."FIG. 51. Marconi Magnetic DetectorFIG. 51. Marconi Magnetic DetectorBut if a rapidly oscillating current is passed through a coil surrounding the iron, a sudden change in magnetization occurs, sufficient to induce an E. M. F. in a second coil surrounding the core and thus operate a telephone receiver in series with this coil.The usual form of magnetic detector consists of a belt of fine iron wires passing over two pulleys which are driven by clockwork. A pair of permanent magnets supply the field which induces a continuously varying magnetization in the moving core. The core passes through the centre of a double coil, one part of which is connected to the telephone receivers and the others to the aerial and ground.
LESSON TWENTY-TWO. DETECTORS.The little bobbins of the telephone receivers exert a very powerful choking action upon the currents of high frequency which effectually blocks their passage and prevents them from having any action upon the receiver.The purpose of the detector is to change these currents into such as will flow readily through the magnets of the telephone receiver and manifest themselves as sounds recognizable from their duration and periodicity as signals of the telegraph code.FIG. 45. Electrolytic Detector.FIG. 45. Electrolytic Detector.Probably the most well known form is the electrolytic detector which consists of an exceedingly fine platinum wire dipping into a cup of dilute nitric acid far enough to just touch the surface of the liquid. The telephone receivers are connected to the detector, in series with a battery. The current from the detector causes bubbles to continuously form on the end of the wire and insulate it from the liquid so that the current cannot flow. When the aerial is struck by a wave, the feeble alternating currents break down the bubbles and permit the currents to flow, causing a sound in the telephone receivers.The detectors in most common use to-day are of the crystal or rectifying type. There are a great many different forms of this type of detector, each one of which possesses certain features making it peculiarly adaptable under certain circumstances.FIG. 46. Silicon Detector.FIG. 46. Silicon Detector.The silicon detector consists of a flat surface of highly polished silicon upon which rests a brass point.The Pyron detector is composed of a crystal of iron pyrites embedded in a cup of fusible metal. A small wire spring bears against the surface of the crystal. The Pyron detector is somewhat harder to adjust than other forms of crystal detector, but remains in a sensitive condition much longer.FIG. 47. Perikon Detector.FIG. 47. Perikon Detector.The Perikon detector consists of a cup of fusible alloy in which are imbedded several pieces of a mineral called zincite. Another cup containing a fragment of chalcopyrites or bornite is held in a cup carried on the end of a rotating rod. The chalcopyrites is brought into contact with one of the crystals of zincite and the pressure adjusted by means of a spring. The Perikon detector will operate without a battery, but that latter is necessary in order to obtain the best results when receiving faint or far away signals.FIG. 48. Galena Detector.FIG. 48. Galena Detector.The Perikon Electra detector is a very sensitive form of the regular Perikon detector fitted with a micrometer adjustment.The Galena detector consists of a crystal of that material to which contact is made by means of a fine wire spring exerting very light pressure.FIG. 49. Audion Detector.FIG. 49. Audion Detector.Crystal detectors act as rectifiers and change the alternating currents Into direct currents, which will pass through the telephone receivers. Minerals used for this purpose are said to possessunilateral conductivity, that is, they conduct currents better in one direction than the other and act much the same as a valve which allows water to flow in one direction, but not in the other.Another well known detector of the "valve" type is that known as theAudion, consisting of a small incandescent lamp containing a small grid and plate of nickel. When the lamp is lighted by connecting a battery to the filament, a flow of ions passing from the hot filament through the grid to the plate is set up. The grid and plate form part of the receiving circuit containing the telephones. The flow of ions carries the oscillatory currents from the grid to the plate, but does not allow them to pass back again. In this manner, the alternating oscillatory currents are converted into direct currents, which will pass through the telephone receivers.FIG. 50. Carborundum Detector.FIG. 50. Carborundum Detector.The Carborundum detector, as its name implies, is a device making use of theunilateral conductivityof carborundum. This form of detector is very sensitive and has been employed for a number of years in all the installations of the United Wireless Telegraph Co.It consists of a small crystal of carborundum clamped tightly between two carbon electrodes. It may be used with or without a battery. The battery is preferred.The Magnetic detector is a very sensitive device utilizing the changes in the magnetic state of iron, which are caused by rapidly oscillating currents. If a core of iron wires be placed in a varying magnetic field, the magnetization of the iron will lag behind the magnetizing force on account ofhysteresisor "magnetic friction."FIG. 51. Marconi Magnetic DetectorFIG. 51. Marconi Magnetic DetectorBut if a rapidly oscillating current is passed through a coil surrounding the iron, a sudden change in magnetization occurs, sufficient to induce an E. M. F. in a second coil surrounding the core and thus operate a telephone receiver in series with this coil.The usual form of magnetic detector consists of a belt of fine iron wires passing over two pulleys which are driven by clockwork. A pair of permanent magnets supply the field which induces a continuously varying magnetization in the moving core. The core passes through the centre of a double coil, one part of which is connected to the telephone receivers and the others to the aerial and ground.
LESSON TWENTY-TWO. DETECTORS.The little bobbins of the telephone receivers exert a very powerful choking action upon the currents of high frequency which effectually blocks their passage and prevents them from having any action upon the receiver.The purpose of the detector is to change these currents into such as will flow readily through the magnets of the telephone receiver and manifest themselves as sounds recognizable from their duration and periodicity as signals of the telegraph code.FIG. 45. Electrolytic Detector.FIG. 45. Electrolytic Detector.Probably the most well known form is the electrolytic detector which consists of an exceedingly fine platinum wire dipping into a cup of dilute nitric acid far enough to just touch the surface of the liquid. The telephone receivers are connected to the detector, in series with a battery. The current from the detector causes bubbles to continuously form on the end of the wire and insulate it from the liquid so that the current cannot flow. When the aerial is struck by a wave, the feeble alternating currents break down the bubbles and permit the currents to flow, causing a sound in the telephone receivers.The detectors in most common use to-day are of the crystal or rectifying type. There are a great many different forms of this type of detector, each one of which possesses certain features making it peculiarly adaptable under certain circumstances.FIG. 46. Silicon Detector.FIG. 46. Silicon Detector.The silicon detector consists of a flat surface of highly polished silicon upon which rests a brass point.The Pyron detector is composed of a crystal of iron pyrites embedded in a cup of fusible metal. A small wire spring bears against the surface of the crystal. The Pyron detector is somewhat harder to adjust than other forms of crystal detector, but remains in a sensitive condition much longer.FIG. 47. Perikon Detector.FIG. 47. Perikon Detector.The Perikon detector consists of a cup of fusible alloy in which are imbedded several pieces of a mineral called zincite. Another cup containing a fragment of chalcopyrites or bornite is held in a cup carried on the end of a rotating rod. The chalcopyrites is brought into contact with one of the crystals of zincite and the pressure adjusted by means of a spring. The Perikon detector will operate without a battery, but that latter is necessary in order to obtain the best results when receiving faint or far away signals.FIG. 48. Galena Detector.FIG. 48. Galena Detector.The Perikon Electra detector is a very sensitive form of the regular Perikon detector fitted with a micrometer adjustment.The Galena detector consists of a crystal of that material to which contact is made by means of a fine wire spring exerting very light pressure.FIG. 49. Audion Detector.FIG. 49. Audion Detector.Crystal detectors act as rectifiers and change the alternating currents Into direct currents, which will pass through the telephone receivers. Minerals used for this purpose are said to possessunilateral conductivity, that is, they conduct currents better in one direction than the other and act much the same as a valve which allows water to flow in one direction, but not in the other.Another well known detector of the "valve" type is that known as theAudion, consisting of a small incandescent lamp containing a small grid and plate of nickel. When the lamp is lighted by connecting a battery to the filament, a flow of ions passing from the hot filament through the grid to the plate is set up. The grid and plate form part of the receiving circuit containing the telephones. The flow of ions carries the oscillatory currents from the grid to the plate, but does not allow them to pass back again. In this manner, the alternating oscillatory currents are converted into direct currents, which will pass through the telephone receivers.FIG. 50. Carborundum Detector.FIG. 50. Carborundum Detector.The Carborundum detector, as its name implies, is a device making use of theunilateral conductivityof carborundum. This form of detector is very sensitive and has been employed for a number of years in all the installations of the United Wireless Telegraph Co.It consists of a small crystal of carborundum clamped tightly between two carbon electrodes. It may be used with or without a battery. The battery is preferred.The Magnetic detector is a very sensitive device utilizing the changes in the magnetic state of iron, which are caused by rapidly oscillating currents. If a core of iron wires be placed in a varying magnetic field, the magnetization of the iron will lag behind the magnetizing force on account ofhysteresisor "magnetic friction."FIG. 51. Marconi Magnetic DetectorFIG. 51. Marconi Magnetic DetectorBut if a rapidly oscillating current is passed through a coil surrounding the iron, a sudden change in magnetization occurs, sufficient to induce an E. M. F. in a second coil surrounding the core and thus operate a telephone receiver in series with this coil.The usual form of magnetic detector consists of a belt of fine iron wires passing over two pulleys which are driven by clockwork. A pair of permanent magnets supply the field which induces a continuously varying magnetization in the moving core. The core passes through the centre of a double coil, one part of which is connected to the telephone receivers and the others to the aerial and ground.
The little bobbins of the telephone receivers exert a very powerful choking action upon the currents of high frequency which effectually blocks their passage and prevents them from having any action upon the receiver.
The purpose of the detector is to change these currents into such as will flow readily through the magnets of the telephone receiver and manifest themselves as sounds recognizable from their duration and periodicity as signals of the telegraph code.
FIG. 45. Electrolytic Detector.FIG. 45. Electrolytic Detector.
FIG. 45. Electrolytic Detector.
Probably the most well known form is the electrolytic detector which consists of an exceedingly fine platinum wire dipping into a cup of dilute nitric acid far enough to just touch the surface of the liquid. The telephone receivers are connected to the detector, in series with a battery. The current from the detector causes bubbles to continuously form on the end of the wire and insulate it from the liquid so that the current cannot flow. When the aerial is struck by a wave, the feeble alternating currents break down the bubbles and permit the currents to flow, causing a sound in the telephone receivers.
The detectors in most common use to-day are of the crystal or rectifying type. There are a great many different forms of this type of detector, each one of which possesses certain features making it peculiarly adaptable under certain circumstances.
FIG. 46. Silicon Detector.FIG. 46. Silicon Detector.
FIG. 46. Silicon Detector.
The silicon detector consists of a flat surface of highly polished silicon upon which rests a brass point.
The Pyron detector is composed of a crystal of iron pyrites embedded in a cup of fusible metal. A small wire spring bears against the surface of the crystal. The Pyron detector is somewhat harder to adjust than other forms of crystal detector, but remains in a sensitive condition much longer.
FIG. 47. Perikon Detector.FIG. 47. Perikon Detector.
FIG. 47. Perikon Detector.
The Perikon detector consists of a cup of fusible alloy in which are imbedded several pieces of a mineral called zincite. Another cup containing a fragment of chalcopyrites or bornite is held in a cup carried on the end of a rotating rod. The chalcopyrites is brought into contact with one of the crystals of zincite and the pressure adjusted by means of a spring. The Perikon detector will operate without a battery, but that latter is necessary in order to obtain the best results when receiving faint or far away signals.
FIG. 48. Galena Detector.FIG. 48. Galena Detector.
FIG. 48. Galena Detector.
The Perikon Electra detector is a very sensitive form of the regular Perikon detector fitted with a micrometer adjustment.
The Galena detector consists of a crystal of that material to which contact is made by means of a fine wire spring exerting very light pressure.
FIG. 49. Audion Detector.FIG. 49. Audion Detector.
FIG. 49. Audion Detector.
Crystal detectors act as rectifiers and change the alternating currents Into direct currents, which will pass through the telephone receivers. Minerals used for this purpose are said to possessunilateral conductivity, that is, they conduct currents better in one direction than the other and act much the same as a valve which allows water to flow in one direction, but not in the other.
Another well known detector of the "valve" type is that known as theAudion, consisting of a small incandescent lamp containing a small grid and plate of nickel. When the lamp is lighted by connecting a battery to the filament, a flow of ions passing from the hot filament through the grid to the plate is set up. The grid and plate form part of the receiving circuit containing the telephones. The flow of ions carries the oscillatory currents from the grid to the plate, but does not allow them to pass back again. In this manner, the alternating oscillatory currents are converted into direct currents, which will pass through the telephone receivers.
FIG. 50. Carborundum Detector.FIG. 50. Carborundum Detector.
FIG. 50. Carborundum Detector.
The Carborundum detector, as its name implies, is a device making use of theunilateral conductivityof carborundum. This form of detector is very sensitive and has been employed for a number of years in all the installations of the United Wireless Telegraph Co.
It consists of a small crystal of carborundum clamped tightly between two carbon electrodes. It may be used with or without a battery. The battery is preferred.
The Magnetic detector is a very sensitive device utilizing the changes in the magnetic state of iron, which are caused by rapidly oscillating currents. If a core of iron wires be placed in a varying magnetic field, the magnetization of the iron will lag behind the magnetizing force on account ofhysteresisor "magnetic friction."
FIG. 51. Marconi Magnetic DetectorFIG. 51. Marconi Magnetic Detector
FIG. 51. Marconi Magnetic Detector
But if a rapidly oscillating current is passed through a coil surrounding the iron, a sudden change in magnetization occurs, sufficient to induce an E. M. F. in a second coil surrounding the core and thus operate a telephone receiver in series with this coil.
The usual form of magnetic detector consists of a belt of fine iron wires passing over two pulleys which are driven by clockwork. A pair of permanent magnets supply the field which induces a continuously varying magnetization in the moving core. The core passes through the centre of a double coil, one part of which is connected to the telephone receivers and the others to the aerial and ground.