L. DE FOREST. OSGILLATION RESPONSIVE DEVICE.

APPLICATION FILED MAY 19.1906.

WIT ESSE 5:

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- PATENTED NOV. 13, 1906;

UNITED STATES PATENT OFFICE;

LE-E'DE FOREST, OF NEW YORK, N. Y.

OSClLLATlON-RESPONSIVE DEVICE.

- Nassau-7o.

Patented Nov. 13, 1906.

Original application and January 1B, 1906. Serial n. 296,616. Divided and as application filed May 19,1906.

Serial in. 311,721.

i at all whom nmy-cbncern:

M invention relates to devices for detectsimplicity and 'sensitiveness and one ing eeble electrical'currents or oscillations, in general, and ecially such currents or oscillations which are developed in wirelesstelegraph-receiving system's.

The object of my invent on is to provide onder of reat- 3 an oscillationdetector or r which, inasmuch as it does-not depend for its operation u on any variation of resistance of an impe ect electrical contact or any variation of the a parent resistance or counter electromotive orce of a polarization'cell, requiresno adjustment when employed for receiving wireless-telegra signals.

h: With these ob'ects in view, my invention comprises 'a receptacle inclosing a sensitive,-

gaseous conducting medium; a. wave-interce'pting means associated with said gaseous conducting medium whereby the feeble elec- 'trical currents or oscillations resulting from the 'energ absorbed from electromagnetic signal-waves may be impressed upon,said

gaseous conducting medium to alter its conuctivity; and a l-indicating device operatively connect with said gaseous conducting medium whereby alterations in the conductivity of the latter may be made 111 anifest. I

My invention may best be understood by having reference .to, the drawing which accompanies and form'sa part of this specifiw tion and which illustrates diagrammatically one embodiment of'm invention.

In the drawing,- wirelem-telegrap e figure represents a system pro vided with one form of the oscillation onsive' device which constitutes the sub ect-.

matter of the present invention.

In t figure, tenna connected with the I are incl A represents a. receiving-an- The elepto earth at E and associated rece tacle B. .Two electrodes 6 and, osefiwithin said receptacle, whichmay be partially exhausted, and, as shown,

' trode C may be an ordinary incandescentlamp carbon filament, which isconnected witha battery or other source of electrical energy D. The electrode I may be any suitable conductor and is herein shown as a disk of platinum or other. material. The gaseous medium inclo'sed between the electrodes 0 and I is rendered sensitive to electrical oscil lations by the radiation of heat from the electrode C, said electrode bein heated by 'the' source of ener D. The local circuit l containing the battery H or other source of electrical energy and thetelephone F or other signal-indicating device is electrically conshown is connected in series therewith. The i antenna A may be associated with either electrode andin such case the other electrode ma be connect-ed to earth. It will be un erstood, however, that the particular mode of as ociating the oscillation respon sive device with the antenna forms no part of my invention and that any suitable sys tem of circuits may oscillation responsive device.

The electro es C and I by the battery H depends upon the nature of the gas intervening be- .tween'said electrodes and upon the degree of exhaustion maintained within the receptacle B. I have found that from twenty-five to one hundred and ten volts is sufficient and by em lo a a-much smal er yo ltage may be used. The conductivity of the gas, which may be air, or a gas containing compounds of the halogens or halogen's alts or which may be mercury vapor, is increased suflicientlfy to render said as sensitive to the passa e 0 electrical oscilations across the ga y the radiation of heat from the electr e C. The passage of electrical oscillations acrosssaid gap alters the conductivity of the gas in said gap, prob ably by changing the speed of the ions in said gas, and thereby current variations are prouced in the circuit containing the battery H, the electrodes C and I, and t e telephone F, causing said telephone. to respond. en the telephonqis in series with the battery H and the electrodes C and oscillations across the gap between said elec trodes causes an increase of current through a the telephone and if the telephone is connectotential to be'impre'ssed upon the I, the passage of be employed with said hi her degree of exhaustion cation, Serial No. 296,615, filed January 18,

. ed in shunt with said electrodes, the passage I claim 1. oscillation-responsive device comprising a partially-exhausted receptacle, two separated electrodes sealed in said'receptacle, means for heating-one only of said electrodes, means whereby electrical oscillations may be impressed upon the gaseous medium between said electrodes, and a intervening a source of electrical local circuit including ener and a signal-indicatin .device electrica connected with-said e ectrodesa .2. oscillation-responsive device coinprising a partially-exhausted receptacle, two

.prising a separated e ectrodes sealed in said receptaseparated electrodes sealed in said recepta cle, means for heating one only of said elec trodes, means whereby electrical oscillations may be impressed upon the gaseous medium intervening between said electrodes, and a local circuit including a source of electrical energy and a signal-indicating device connected in series with said electrodes.

3. An oscillation-responsive device comprising a partially-exhausted rece tacle, two separated electrodes sealed in sand receptacle, a source of electric current so associated with one only of said electrodes as to render the gaseous medium intervening between said electrodes sensitive to electrical oscillations, and a local circuit includin a source of electrical energy and a signal-indicating device electrically connected with said electrodes.

4. An oscillation-responsive device comartiallyexhausted receptacle;

ole, means for heating one only of said elec 111 between said electrodes, and a local circuit including a source of electrical energy' trodes, and a local circuit including a source of electrical energy and a signal mdicating device electrically connected with said electrodes. Y

5. An oscillation-responsive device comprising a receptacle, two separated electrodes inclosed within said receptacle, means 5 5 for heating one only of said electrodes, means whereby electrical oscillations may be impressed upon the gaseous medium intervenmg between said electrodes, and a local cir curt includin a source of electrical ener anda si a-indicating device electrica y connects with said electrodes. 6. An'oscillationeresponsive device comprising a receptacle, two separated elec trodes inclosed within said receptacle, means for heating one only of said electrodes, means whereby electrical oscillations may be impressed upon the gaseous medium interven- 7C and a signaLmdicating device connected in series with said electrodes.

7. An oscillation-responsive device com. prising a rece tacle, two separated electrodes inclos within said receptacle, a

' source of electric current so associated with a one only of said electrodes as to render the gaseous medium intervening between said electrodes sensitive to electrical oscillations, and a local circuit including a source of elec- 8o trical energy and a signal-indicating-device electrically connected with said electrodes.

.8. An oscillation-responsive device comprising a receptacle, two separated electrodes inclosed within said receptacle, means forheating one only of said electrodes, and a local circuit including a source of electrical ener and a signal-indicatin device electrica y connected with said e ectrodes.

' In testimony whereof I have hereunto sub- 0 scribed my name this -l0th day of May, 1906.

DE -FOREST.

Witnesses: V

PHILIP Fmswonrs, GEO. L. LEWIS.