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Publication numberUS2531830 A
Publication typeGrant
Publication date28 Nov 1950
Filing date16 Aug 1944
Priority date16 Aug 1944
Publication numberUS 2531830 A, US 2531830A, US-A-2531830, US2531830 A, US2531830A
InventorsSimpson Albert R
Original AssigneeSimpson Albert R
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Voltage pulse generator
US 2531830 A
Abstract  available in
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Claims  available in
Description  (OCR text may contain errors)

NGV. 28, A R SIMPSON VOLTAGE PULSE GENERATQR Filed Aug. 16, 1944 INVENTOR. Z/W jzpfon/ VBY Patented Nov. 28, 1950 VOLTAGE PULSE GENERATOR Albert R. Simpson, Knoxville, Tenn., assignor to the United States of America as represented by the United States Atomic Energy Commission Application August 16, 1944, Serial No. 549,737

(Cl. Z50-36) 3 Claims.

This invention relates to circuit arrangements for producing pulses of electrical energy and has for its principal object the provision of an improved source of periodic short sharp voltage pulses of known frequency and intensity.

It is frequently desirable to have available such a source of voltage pulses which is especially useful in the testing and Calibrating of counter circuits where it is desirable to simulate the Waveshape and frequency of pulses produced by ionization chambers, G-M counters and the like.

The present invention provides a means for furnishing short sharp pulses the frequency and intensity of which may be varied over wide ranges and the polarity of which may be selected.

In the practice of the invention the discharge time of a relaxation oscillator determines the duration of the pulse while the charging time determines the interval between pulses, i. e., the frequency. In the preferred embodiment of the invention, this is accomplished by employingl a thyratron tube in the relaxation circuit and connecting its control electrode to the control grid of a suitable amplifier tube so that Whenever the thyratron is conducting, a signal voltage is impressed on the grid of the amplifier tube.

My invention will be better understood from the following description when read in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the drawing, the single figure shows a circuit network supplied with direct current by a suitable source I` which for simplicity is here shown as a battery. Current owing through a resistance II furnishes a voltage for charging a condenser I2 through resistances I3 and I4. A thyratron tube I5 in series with a resistance I6 provides a discharge path for the condenser I2 when it has charged to the critical potential. It will be appreciated that the circuit thus far described constitutes a relaxation oscillator the frequency of which may be set for diierent ranges by selecting different condensers I2a, I2b, or I2c by means of a selector switch I'I and which ranges can be varied by adjusting resistance I4. When the thyratron I5 discharges the condenser I2, its control electrode I8 goes positive to provide a short sharp signal which is amplified by tubes I9 and 2D and made available for use at output leads 2| and 2Ia. The grid of tube I9 is normally at ground potential and is connected through a limiting resistance 22 and a coupling resistance 23 to receive the positive voltage pulses of the control electrode I8 Whenever the thyratron I5 conducts.

l A resistance 24 between the anode of the tube I9 and the source III and a resistance 25 between its cathode and ground are so selected that when no signal is impressed on its grid it will pass a current suicient to provide a desired voltage drop across the resistance 25 therebymaking its grid negative with respect to its cathode. The second amplifier tube 2I| has its anode connected to the source I Il through a resistance 26, its cathode connected to ground through a resistance 2l and its grid connected to its cathode through a resistance 28. The resistances 26 and 21 are preferably equal and so chosen as to have voltage drops corresponding to the magnitude of the signal desired at the output 2 I. A convenient value for these voltage dro-ps has been found to be fty volts.

The operation of the circuit will be readily understood if it is assumed that the condenser I2 is receiving a charge. This charge and therefore the voltage on the anode of the thyratron I5 will increase at a rate determined by the time constant of the condenser I2 and the resistances I3 and I4 circuit until the thyratron I'5 fires to discharge the condenser I2. The momentary current surge through the thyratron I5 creates on its control electrode I'B a positive voltage corresponding in intensity and duration to the current surge. This positive voltage pulse drives the grid of the tube I9 positive to give a corresponding increase in its plate current. This increase in plate current through the tube I9 decreases the voltage on its plate and this sudden decrease in voltage is transferred through a coupling condenser 29 to the grid of the second amplifier tube 20 to drive its negative and practically cut off the current now between its plate and cathode, whereby the voltage drops (fifty volts) across the resistances 2B and 21 appear as voltage pulses in their respective output terminals 2l and 2m. I'hese output voltage pulses Will have the same general wave shape as the discharge current through the thyratron I5.

It will be evident that when the amplifier tube 20 suddenly becomes nonconducting a positive voltage will appear on terminal 2| and a negative voltage pulse will appear on terminal 21a. By means of a switch 3U either of these voltage pulses may be selectively applied through a condenser 3I to a counter circuit 32 which itis desired to test or calibrate.

Although adjustment of the coupling resistance 23 will change the intensity or height of the voltage pulses appearing on the output terminals 2| and 2 la, it has been found convenient to have a means for adjusting the strength of these pulses in known steps and for this purpose a movable Contact arm 33 is arranged for selectively connecting the counter circuit 32 to a condenser 34 and a group of resistances 35, 3B, 31, and 38 which preferably are so proportioned as to attenuate the signal in equal steps and thereby make it possible to check the operation or response of the counter circuit 32 to signals differing a known amount in intensity.

In order that the delivery of signal pulses to the output 2| may be interrupted Without necessitating the deenergization of the several tubes a switch 39 is provided for grounding the signal prior to its being impressed on the grid of the second amplifier tube 2U.

Although a preferred embodiment lof the invention has been illustrated and described to make clear the novel features thereof, it will be obvious to those skilled in the art that the invention may take modified forms to meet various conditions Which may be encountered in different specific uses, and it is therefore intended to cover by the appended claims all such modifications which fall within the spirit and scope of the invention.

I claim:

1. An oscillation generating circuit comprising a gas discharge thyratron tube having a cathode, control grid, and anode electrodes; a source of potential exceeding the value required to ionize the gas between said anode and cathode, resistance means and capacitance means connected in series relationship, said capacitance means being connected in parallel relationship with the discharge path through said tube; and output circuit means for extracting pulses of energy from said tube comprising said control grid and a conductor connected thereto.

2. A pulse generating circuit comprising resistance means, capacitance means, a source of electrical potential connected thereto through said resistance means for charging said capacitance means, a gas-discharge tube having a cathode, anode, and control grid, said tube being connected to furnish a discharge path for said capacitance means; and an output circuit including said control grid, means for maintaining said control grid at a relatively` fixed potential `While said tube is not conducting, and conductive means connected to said control grid for extracting energy therefrom when said tube is rendered conductive.

3. 1n combination, a gas discharge tube having cathode, grid, and anode electrodes; capacitance means, resistance means, and a source of electrical potential connected inthe anode-cathode circuit of said tube to form a relaxation oscillator; and' means for extracting energy from said tube comprising `said grid electrode and a conductor connected thereto.


REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Y Date 2,027,054 Miessner Jan. 7, 1936 2,092,861 Swart Sept. 14, 1937 2,118,626 Smith May 24, 1938 2,144,779 Schlesinger Jan. 24, 1939 2,163,214 SchlesingerV June 20, 1939' 2,170,252 Schlesinger Aug. 22, 1939 2,179,414 Konkle Nov. 7, 1939 2,202,055 Burnett May 7, 1940 2,227,021 Schlesinger Dec. 31, 1940 2,495,095 Murnma July 30, 1946

Patent Citations
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U.S. Classification331/129, 331/75, 330/157
International ClassificationH03K3/55, H03K3/00
Cooperative ClassificationH03K3/55
European ClassificationH03K3/55