| 单词 | voltmeter |
| 例句 | Some of the meters in automobile dashboards, digital cameras, cell phones, and tuner-amplifiers are voltmeters or ammeters. College Physics for AP Courses 2015-08-12T00:00:00Z A voltmeter in the external circuit allows measurement of the potential difference between the two half-cells. Chemistry 2019-02-14T00:00:00Z “How many voltmeters and hammers does one man need?” COVID-19 killed her husband. Now it’s taking the only home her kids have ever known. 2021-08-09T04:00:00Z The police officers seized a laptop, a voltmeter and a report on health conditions among prisoners, Mr. Mounir said. Crackdown by Egypt Draws Attention to an Anniversary It Aimed to Avoid 2016-01-23T05:00:00Z He founded Non-Linear Systems in 1952 and invented the digital voltmeter in 1954 after he decided that analog voltmeters, which displayed current values with a movable needle, were not accurate enough. Andrew Kay, Pioneer in Computing, Dies at 95 2014-09-05T04:00:00Z By connecting resistors to this galvanometer in different ways, you can use it as either a voltmeter or ammeter that can measure a broad range of voltages or currents. College Physics for AP Courses 2015-08-12T00:00:00Z In practice, a voltmeter would report a potential of −0.47 V with its red and black inputs connected to the Pb and Cu electrodes, respectively. Chemistry 2019-02-14T00:00:00Z From little laser things that allow you to size up a room quickly through to gizmos to measure atmospheric pressure, humidity, gas levels in the atmosphere, ammeters and voltmeters. Google Motorola's Project Ara Might Well Work Best For Things That Are Not Smartphones 2013-10-29T16:45:00Z It contains a voltmeter to read a heartbeat. Bits Blog: Beyond Passwords: New Tools to Identify Humans 2013-09-10T11:20:58Z Mr. Kay’s voltmeter used a system of lights to display numeric values. Andrew Kay, Pioneer in Computing, Dies at 95 2014-09-05T04:00:00Z Figure 21.32 A large resistance R placed in series with a galvanometer G produces a voltmeter, the full-scale deflection of which depends on the choice of R . College Physics for AP Courses 2015-08-12T00:00:00Z In prosaic terms, the cat is really a measuring device, like a Geiger counter or a voltmeter. Bringing Schrödinger s Cat to Life 2012-10-09T18:15:11.620Z A small transformer without an iron core, of course, was used to bring the reading within range of a Cardew voltmeter by connecting the voltmeter to the secondary. The inventions, researches and writings of Nikola Tesla With special reference to his work in polyphase currents and high potential lighting 2012-03-28T02:00:22.660Z In the library across from his office building, Betchkal crawled among cables, politely probing each instrument with a voltmeter like a plaid-clad doctor with a stethoscope. Is Silence Going Extinct? 2012-03-15T22:17:17Z A simple modification makes any of these instruments into a voltmeter. Marvels of Scientific Invention An Interesting Account in Non-technical Language of the Invention of Guns, Torpedoes, Submarine Mines, Up-to-date Smelting, Freezing, Colour Photography, and many other recent Discoveries of Science 2011-11-19T03:00:24.517Z If, however, the voltmeter’s resistance is comparable to that of the device being measured, then the two in parallel have a smaller resistance, appreciably affecting the circuit. College Physics for AP Courses 2015-08-12T00:00:00Z Other Tools and Equipment As you go along in electrical work, you'll be adding tools and other equipment, such as a trouble light and maybe an ammeter or voltmeter. Electricity for the 4-H Scientist Idaho Agricultural Extension Service Bulletin 396, June, 1962 2011-11-18T03:00:30.487Z One and the same instrument may be used as an ammeter or as a voltmeter, by providing it with shunts for use as an ammeter, and series resistances for use as a voltmeter. The New Gresham Encyclopedia Volume 4, Part 2: Ebert to Estremadura 2011-04-14T02:00:56.200Z Galvanometers, ammeters, voltmeters, all our delicate instruments, including the chemical balanced, had been rendered inaccurate, hence useless until re-calibrated. I Walked in Arden 2011-04-10T02:00:06.137Z The voltmeter is therefore the same as the ammeter, except that its dial is marked for volts instead of for amperes, and it has to be provided with the resistance coil. Marvels of Scientific Invention An Interesting Account in Non-technical Language of the Invention of Guns, Torpedoes, Submarine Mines, Up-to-date Smelting, Freezing, Colour Photography, and many other recent Discoveries of Science 2011-11-19T03:00:24.517Z One solution to the problem of voltmeters and ammeters interfering with the circuits being measured is to use galvanometers with greater sensitivity. College Physics for AP Courses 2015-08-12T00:00:00Z Other related instruments are the voltmeter and ammeter. Electricity for the 4-H Scientist Idaho Agricultural Extension Service Bulletin 396, June, 1962 2011-11-18T03:00:30.487Z The electrostatic voltmeter mentioned above is the only instrument which is operated by a P.D. instead of a current. The New Gresham Encyclopedia Volume 4, Part 2: Ebert to Estremadura 2011-04-14T02:00:56.200Z Ammeters to measure the volume, and voltmeters to determine the pressure of current supplied to the baths, should also be provided. Encyclopaedia Britannica, 11th Edition, Volume 9, Slice 2 "Ehud" to "Electroscope" 2011-01-29T03:00:23.777Z All the voltmeters and ohmmeters mentioned owe their method of working to what is known as Ohm's law. Marvels of Scientific Invention An Interesting Account in Non-technical Language of the Invention of Guns, Torpedoes, Submarine Mines, Up-to-date Smelting, Freezing, Colour Photography, and many other recent Discoveries of Science 2011-11-19T03:00:24.517Z Null measurements are generally more accurate but are also more complex than the use of standard voltmeters and ammeters, and they still have limits to their precision. College Physics for AP Courses 2015-08-12T00:00:00Z He invented an ammeter, voltmeter, &c., in conjunction with Professor Perry. The New Gresham Encyclopedia. Vol. 1 Part 3 Atrebates to Bedlis The meters usually are voltmeters and ammeters, the former being adapted to read the several voltages of direct currents in the power plant. Cyclopedia of Telephony and Telegraphy, Vol. 2 A General Reference Work on Telephony, etc. etc. Self-registering voltmeters indicate at any moment the potential difference in every tank, and therefore give notice of short circuits occurring at any part of the installation. Encyclopaedia Britannica, 11th Edition, Volume 7, Slice 3 "Convention" to "Copyright" Another is that adjacent particles become charged as the plates of a minute condenser, and so are drawn tightly together as the plates in an electrostatic voltmeter are drawn towards each other. Marvels of Scientific Invention An Interesting Account in Non-technical Language of the Invention of Guns, Torpedoes, Submarine Mines, Up-to-date Smelting, Freezing, Colour Photography, and many other recent Discoveries of Science 2011-11-19T03:00:24.517Z A voltmeter is placed in parallel with the voltage source to receive full voltage and must have a large resistance to limit its effect on the circuit. College Physics for AP Courses 2015-08-12T00:00:00Z The ammeters and voltmeters which we use for the measurement of audion characteristics and the like are usually electromagnetic instruments. Letters of a Radio-Engineer to His Son The voltmeter enables the voltage of the charging generator to be kept above that of the battery, as the latter rises during charge. Cyclopedia of Telephony and Telegraphy, Vol. 2 A General Reference Work on Telephony, etc. etc. Note also the strip "D" on this shelf, with the voltmeter hung from an iron bracket. The Automobile Storage Battery Its Care And Repair The mil-ammeter is so adjusted as to give a maximum current of 1.5 amperes and the voltmeter reads from zero to 150 volts. Respiration Calorimeters for Studying the Respiratory Exchange and Energy Transformations of Man Standard voltmeters and ammeters alter the circuit being measured and are thus limited in accuracy. College Physics for AP Courses 2015-08-12T00:00:00Z Ammeters and voltmeters are alike in their design. Letters of a Radio-Engineer to His Son A convenient way is to connect the terminals of the several cells to jacks on the power board and to terminate the voltmeter in a plug. Cyclopedia of Telephony and Telegraphy, Vol. 2 A General Reference Work on Telephony, etc. etc. If this causes the voltmeter pointer to return to the "0" line, the switch which connects the generator or motor-generator to the ammeter or indicator is defective. The Automobile Storage Battery Its Care And Repair Two leads from the terminals of the manganin coil connect with the voltmeter outside the chamber, and hence the drop in potential can be measured very accurately and as frequently as is desired. Respiration Calorimeters for Studying the Respiratory Exchange and Energy Transformations of Man To produce a galvanometer for use in analog voltmeters and ammeters that have a low resistance and respond to small currents, we use a large loop area A , high magnetic field B , and low-resistance coils. College Physics for AP Courses 2015-08-12T00:00:00Z In the case of the voltmeter, as you know, we have 206a large resistance in series with the current-measuring part for the reason of which I told in Letter 8. Letters of a Radio-Engineer to His Son The electrical power they could measure accurately and easily by simple voltmeters and ammeters. Empire Cadmium tests may be made with any accurate voltmeter which gives readings up to 2.5 volts in divisions of .05 volt. The Automobile Storage Battery Its Care And Repair The voltmeter and mil-ammeter were read every few minutes, the water collected in the water-meter, carefully weighed, and the temperature differences as measured on the two mercury thermometers were recorded every 4 minutes. Respiration Calorimeters for Studying the Respiratory Exchange and Energy Transformations of Man The circuit shown in the figure below includes a resistor R in series with a battery along with an ammeter and voltmeter to measure the current and voltage respectively. College Physics for AP Courses 2015-08-12T00:00:00Z Usually we describe this condition by saying that a voltmeter has a high resistance. Letters of a Radio-Engineer to His Son At full load the voltmeter would indicate 110 plus 26, or 136 volts. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine Connect the plain brass prod to the positive voltmeter binding post. The Automobile Storage Battery Its Care And Repair The subject with which they were all wrestling covered voltmeter tests and relative amperage, principally with regard to battery construction. Radio Boys Loyalty Bill Brown Listens In Suppose you want 10 V to produce a full- scale deflection of a voltmeter containing a 25-Ω galvanometer with a 50-µA sensitivity. College Physics for AP Courses 2015-08-12T00:00:00Z Suppose the ammeter shows a current of one ampere and the voltmeter an e. m. f. of one volt. Letters of a Radio-Engineer to His Son Turn the rheostat handle gradually; as you advance it, the voltmeter needle will advance. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine This voltmeter has a 2.5 and a 25 volt scale, which makes it convenient for battery work. The Automobile Storage Battery Its Care And Repair He turned the knob, and the needle on the voltmeter moved obligingly upwards. Damned If You Don't This voltmeter would not be useful for voltages less than about half a volt, because the meter deflection would be small and difficult to read accurately. College Physics for AP Courses 2015-08-12T00:00:00Z The voltmeter tells us the e. m. f. Letters of a Radio-Engineer to His Son Another way to determine if the battery is fully charged is by means of the voltmeter, as the volts slowly rise to the proper point during the process of charging. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine If this causes the voltmeter pointer to return to the "0" line, the cutout points are stuck together or the cutout is defective, and the generator should be taken apart for inspection. The Automobile Storage Battery Its Care And Repair As he closed the switch, on no-load, the electrostatic voltmeter flopped over instantly, and steadied at just over 80,000 volts. The Ultimate Weapon Ideally, voltmeters and ammeters do not appreciably affect the circuit, but it is instructive to examine the circumstances under which they do or do not interfere. College Physics for AP Courses 2015-08-12T00:00:00Z We read the voltmeter in the plate circuit and the ammeter in that circuit. Letters of a Radio-Engineer to His Son Having assured yourself that the mechanical details are all right, now look at the voltmeter. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine Remove the voltmeter and complete the battery connection. The Automobile Storage Battery Its Care And Repair By not so much as by a vibration of the voltmeter needle, did the apparatus betray any strain as the load mounted swiftly. The Ultimate Weapon First, consider the voltmeter, which is always placed in parallel with the device being measured. College Physics for AP Courses 2015-08-12T00:00:00Z Next we read the voltage impressed on the grid by reading the voltmeter in the grid circuit. Letters of a Radio-Engineer to His Son If by any chance, the needle does not register, or is now back of 0, try changing about the connections or the voltmeter on the back of the switchboard. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine If the polarity of the charging line wires is not known, it may be determined by a voltmeter, in the same way as the batter-, polarity is determined. The Automobile Storage Battery Its Care And Repair The technicians checked their recording voltmeters and ammeters and reported that, sure enough, some ten kilowatts of power at a little less than one hundred fifteen volts D.C. was coming from the Black Suitcase. With No Strings Attached Very little current flows through the voltmeter if its resistance is a few orders of magnitude greater than the device, and so the circuit is not appreciably affected. College Physics for AP Courses 2015-08-12T00:00:00Z It is easier to use a “voltmeter” which is an instrument for measuring e. m. f.’s. Letters of a Radio-Engineer to His Son The main switch should be so wired that when open it will throw all the current off the line, but still leave the field coils, the voltmeter, and the switchboard lamp in circuit. Electricity for the farm Light, heat and power by inexpensive methods from the water wheel or farm engine If they are, separate them and see if the voltmeter pointer returns to the "0" line. The Automobile Storage Battery Its Care And Repair It was tested calorimetrically, and also by the three voltmeter method, which, however, proved to be too insensitive. On Laboratory Arts The voltage across the device is not the same as when the voltmeter is out of the circuit. College Physics for AP Courses 2015-08-12T00:00:00Z If we connect a voltmeter to the battery X as in Fig. Letters of a Radio-Engineer to His Son Then came the instruments of precision—the electrometer, the resistance bridge, the ammeter, the voltmeter—all of the utmost value in the science. Electricity for Boys If this causes the voltmeter pointer to return to the "0" line, the starting switch is defective. The Automobile Storage Battery Its Care And Repair The plates were 41¾ inches apart, and at the end of the run the voltmeter across the terminals read 20. Scientific American Supplement, No. 1157, March 5, 1898 This allows construction of voltmeters with greater resistance and ammeters with smaller resistance than when less sensitive galvanometers are used. College Physics for AP Courses 2015-08-12T00:00:00Z We must be careful that the voltmeter is so made that it won’t offer too easy a path for electrons to follow. Letters of a Radio-Engineer to His Son Despite the fact that the voltmeter seemed to be shorted out by the relux plate, the needle pointed steadily at twenty-two. Islands of Space To make the voltmeter test, hold the meter wires on the battery terminals, or the terminals of either end cell. The Automobile Storage Battery Its Care And Repair The rays converge in the telescope on metal cells, heating them, and thereby generating a small electric current, the voltage of which is read an a calibrated voltmeter similar to that used with the thermo-couple. The Working of Steel Annealing, Heat Treating and Hardening of Carbon and Alloy Steel Consider what happens if you connect the battery directly to a standard voltmeter as shown in Figure 21.37. College Physics for AP Courses 2015-08-12T00:00:00Z Of course, we must let a small stream of electrons flow through the voltmeter so as to make the pointer move. Letters of a Radio-Engineer to His Son The voltmeter gave a slight kick, then remained steady. Islands of Space If this causes the voltmeter pointer to return to the "0" line, the cutout is defective and a new one should be installed, unless the trouble can be found by inspection and repaired. The Automobile Storage Battery Its Care And Repair In most pyrometers, of course, the temperatures are inscribed directly on the voltmeter, but the fact remains that it is the voltage of a small electric current, and not heat, that is actually measured. The Working of Steel Annealing, Heat Treating and Hardening of Carbon and Alloy Steel However, standard voltmeters need a current to operate; thus, another technique is needed. College Physics for AP Courses 2015-08-12T00:00:00Z That is why voltmeters of this kind are made out of a long piece of fine wire or else have a coil of fine wire in series with the current-measuring part. Letters of a Radio-Engineer to His Son The swing of a voltmeter needle showed how firmly the substance resisted the claw's touch, thus indicating its hardness or softness. Tom Swift and The Visitor from Planet X Each prong carries a binding post, a low reading voltmeter being connected to these posts while the test is made. The Automobile Storage Battery Its Care And Repair Both voltmeters are fitted with keys, so that they are only put in circuit when the readings are taken. Scientific American Supplement, No. 711, August 17, 1889 Figure 21.37 An analog voltmeter attached to a battery draws a small but nonzero current and measures a terminal voltage that differs from the emf of the battery. College Physics for AP Courses 2015-08-12T00:00:00Z Now connect a voltmeter to the two ends of the coil as shown in the figure. Letters of a Radio-Engineer to His Son A Gramme alternator was coupled to the low pressure coil of a transformer, and a hot wire voltmeter put across the primary circuit. Scientific American Supplement, No. 795, March 28, 1891 If this is done, the elevated shelf should also be installed, as it is a great convenience for the hydrometer, voltmeter, and so on, as already described. The Automobile Storage Battery Its Care And Repair The voltmeter, V2, immediately above this resistance, serves to indicate the difference of potential at the machine terminals. Scientific American Supplement, No. 711, August 17, 1889 The uncertainty in this calculation can be considerably smaller than when using a voltmeter directly, but it is not zero. College Physics for AP Courses 2015-08-12T00:00:00Z The voltmeter tells in volts how much e. m. f. is being applied to force the current through the coil. Letters of a Radio-Engineer to His Son On putting a condenser on the high pressure circuit, the voltmeter wire fused. Scientific American Supplement, No. 795, March 28, 1891 If the voltmeter pointer does not return to the "0" line, replace the cable and wires on the starting switch terminal and proceed as follows: Defective Switches. The Automobile Storage Battery Its Care And Repair The instruments used for measuring were Ayrton's amperemeter and Deprez's voltmeter, which had been tested in the exhibition by the Commission for Experiments on Electrical Instruments, under the presidency of Professor Rousseau. Scientific American Supplement, No. 530, February 27, 1886 Two configurations for ohmmeters using standard voltmeters and ammeters are shown in Figure 21.39. College Physics for AP Courses 2015-08-12T00:00:00Z We get a new pair of values for EC and IB, getting EC from the voltmeter and IB from the ammeter. Letters of a Radio-Engineer to His Son The volt side of the dial may be calibrated in the same manner, using a voltmeter instead of the ammeter. The Boy Mechanic: Volume 1 700 Things for Boys to Do If they are not, open them and see if the voltmeter pointer returns to the "0" line. The Automobile Storage Battery Its Care And Repair The indicating instruments were of the crudest construction, consisting of two voltmeters connected by "pressure wires" to the centre of electrical distribution. Edison, His Life and Inventions The resistor could be anything from a light bulb to a voltmeter. College Physics for AP Courses 2015-08-12T00:00:00Z A voltmeter shows the value of this e. m. f. and an ammeter tells the strength of the electron stream. Letters of a Radio-Engineer to His Son At the place mark the number of volts the cell reads when connected with a voltmeter. The Boy Mechanic: Volume 1 700 Things for Boys to Do If this causes the voltmeter pointer to return to the "0" line, the switches are defective. The Automobile Storage Battery Its Care And Repair Every battery attendant should be provided with a hydrometer and a voltmeter. The Project Gutenberg Encyclopedia Volume 1 of 28 Profs. Ayrton and Perry lately described and exhibited before the Physical Society their new ammeters and voltmeters, also a non-sparking key. Scientific American Supplement, No. 433, April 19, 1884 An A.C. voltmeter can, of course, be substituted for the lamps, or a D.C. voltmeter with D.C. current can be used in making the tests. Oxy-Acetylene Welding and Cutting Electric, Forge and Thermit Welding together with related methods and materials used in metal working and the oxygen process for removal of carbon The filament voltmeter is connected across the filament secondary coil terminals, while the plate milli-ammeter is connected to the mid-taps of the plate secondary coil and the filament secondary coil. The Radio Amateur's Hand Book Connections of Cadmium Leads: In making Cadmium Tests, connect the prod which has the cadmium fastened to it to the negative voltmeter binding post. The Automobile Storage Battery Its Care And Repair The voltmeter should read up to about 3 volts and be fitted with a suitable connector to enable contacts to be made quickly with any desired cell. The Project Gutenberg Encyclopedia Volume 1 of 28 The well known ammeters and voltmeters of the authors used for electric light work are now constructed so as to dispense with a constant, and give the readings in amperes and volts without calculation. Scientific American Supplement, No. 433, April 19, 1884 Downstairs the masked master criminal had already attached a voltmeter to the wires he had installed, waiting. The Exploits of Elaine To measure the pressure of a current in volts an instrument called a voltmeter is used, as shown at C in Fig. The Radio Amateur's Hand Book If neither terminal is marked, the polarity may be determined with a voltmeter, or by a cadmium test. The Automobile Storage Battery Its Care And Repair A photograph of the switchboard at Greenock where this booster is in use shows the voltmeter needle as if it had been held rigid, although the exposure lasted 90 minutes. The Project Gutenberg Encyclopedia Volume 1 of 28 By means of an ammeter and voltmeter used conjointly, the resistance of part of the circuit, say a lamp or heated wire, can be got by Ohm's law. Scientific American Supplement, No. 433, April 19, 1884 Below, the master criminal could scarcely refrain from exclaiming with satisfaction as his voltmeter registered the powerful current that was passing. The Exploits of Elaine To do this you need only to use a voltmeter across the filament terminals instead of an ammeter in series with it; then regulate the voltage of the filament with a rheostat. The Radio Amateur's Hand Book The Cadmium Tester consists of a voltmeter, Fig. The Automobile Storage Battery Its Care And Repair "My voltmeter," he said, reading it, "shows that there is a current of about 1.8 volts passing through this pipe all the time." The War Terror If no such voltmeter is available, a simple test is to fill a tumbler with weak electrolyte or salt water and insert two wires attached to the line. The Automobile Storage Battery Its Care And Repair This test may be made by using a voltmeter instead of lamps, as shown in Fig. The Automobile Storage Battery Its Care And Repair For this transmitter a direct current voltmeter reading from 0 to 15 volts is used. The Radio Amateur's Hand Book A length of flexible wire having a terminal at one end is soldered to each prod for attachment to the voltmeter. The Automobile Storage Battery Its Care And Repair If a voltmeter is used, be especially careful to have the part projecting above the liquid perfectly dry. The Automobile Storage Battery Its Care And Repair Don't fail to use a voltmeter to find the proper temperature of the filament. The Radio Amateur's Hand Book |
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