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Electrostatic voltmeter can refer to an electrostatic charge meter, known also as surface DC voltmeter, or to a voltmeter to measure large electrical potentials, traditionally called electrostatic voltmeter.
A surface DC voltmeter is an instrument that measures voltage with no electric charge transfer. [ citation needed ]
It can accurately measure surface potential (voltage) on materials without making physical contact, and so there is no electrostatic charge transfer or loading of the voltage source.
Many voltage measurements cannot be made using conventional contacting voltmeters because they require charge transfer to the voltmeter, thus causing loading and modification of the source voltage. For example, when measuring voltage distribution on a dielectric surface, any measurement technique that requires charge transfer, no matter how small, will modify or destroy the actual data.
In practice, an electrostatic charge monitoring probe is placed close (1 mm to 5 mm) to the surface to be measured, and the probe body is driven to the same potential as the measured unknown by an electronic circuit. This achieves a high-accuracy measurement that is virtually insensitive to variations in probe-to-surface distances. The technique also prevents arc-over between the probe and measured surface when measuring high voltages.
The operating principle of an electrostatic voltmeter is similar to that of an electrometer; it is, however, designed to measure high potential differences, typically from a few hundred to many thousands volts.
An electrostatic voltmeter uses the attraction force between two charged surfaces to create a deflection of a pointer directly calibrated in volts. Since the attraction force is the same regardless of the polarity of the charged surfaces (as long as the charge is opposite), the electrostatic voltmeter can measure DC voltages of either polarity.
Typical construction is shown in the drawing. The pivoted sector NN is attracted to the fixed sector QQ. The small weight w counterbalances the moving sector and indicates the voltage by the pointer P. In newer instruments, the weight is replaced by a spring, thus allowing the meter to be used in horizontal and vertical positions; this form is shown in the photograph. The fixed sector is insulated from the rest of the meter. The butterfly-shaped moving industry is made of thin aluminum foil. To minimize high electrical stress, the fixed and moving sectors are highly polished without sharp corners. An electrostatic voltmeter uses the attraction force between two charged surfaces to create a deflection of a pointer directly calibrated in volts.
Since the attraction force is the same regardless of the polarity of the charged surfaces (as long as the charge is opposite), the electrostatic voltmeter can measure DC voltages of either polarity. The instrument will draw negligible current from a DC source. It can also be used on AC and will draw a small current due to the capacitance of the rotor system. To reduce the torque required and improve the sensitivity and speed of response, a small mirror attached to the rotor may replace the pointer with a light beam deflected by it over a scale. [1]
An ammeter is an instrument used to measure the current in a circuit. Electric currents are measured in amperes (A), hence the name. For direct measurement, the ammeter is connected in series with the circuit in which the current is to be measured. An ammeter usually has low resistance so that it does not cause a significant voltage drop in the circuit being measured.
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the volt (V).
A voltmeter is an instrument used for measuring electric potential difference between two points in an electric circuit. It is connected in parallel. It usually has a high resistance so that it takes negligible current from the circuit.
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A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the flow of current more precisely.
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A solenoid voltmeter is a specific type of voltmeter electricians use to test electrical power circuits. It uses a solenoid coil to attract a spring-loaded plunger; the movement of the plunger is calibrated in terms of approximate voltage. It is more rugged than a D'arsonval movement, but neither as sensitive nor as precise.
An electrostatic fieldmeter, also called a static meter is a tool used in the static control industry. It is used for non-contact measurement of electrostatic charge on an object. It measures the force between the induced charges in a sensor and the charge present on the surface of an object. This force is converted to volts, measuring both the initial peak voltage and the rate at which it falls away.
A test probe is a physical device used to connect electronic test equipment to a device under test (DUT). Test probes range from very simple, robust devices to complex probes that are sophisticated, expensive, and fragile. Specific types include test prods, oscilloscope probes and current probes. A test probe is often supplied as a test lead, which includes the probe, cable and terminating connector.
The Volta potential in electrochemistry, is the electrostatic potential difference between two metals that are in contact and are in thermodynamic equilibrium. Specifically, it is the potential difference between a point close to the surface of the first metal and a point close to the surface of the second metal.
A potentiometer is an instrument for measuring voltage or 'potential difference' by comparison of an unknown voltage with a known reference voltage. If a sensitive indicating instrument is used, very little current is drawn from the source of the unknown voltage. Since the reference voltage can be produced from an accurately calibrated voltage divider, a potentiometer can provide high precision in measurement. The method was described by Johann Christian Poggendorff around 1841 and became a standard laboratory measuring technique.
A Megohmmeter or insulation resistance tester, also colloquially known as megger, is a special type of ohmmeter used to measure the electrical resistance of insulators. Insulating components, for example cable jackets, must be tested for their insulation strength at the time of commissioning and as part of maintenance of high voltage electrical equipment and installations.
Explorer 54, also called as AE-D, was a NASA scientific satellite belonging to series Atmosphere Explorer, being launched on 6 October 1975 from Vandenberg Air Force Base board a Thor-Delta 2910 launch vehicle.
Explorer 31, also called DME-A, was a NASA satellite launched as part of the Explorer program. Explorer 31 was launched on 29 November 1965 from Vandenberg Air Force Base, California, with a Thor-Agena launch vehicle. Explorer 31 was released along with the Canadian satellite Alouette 2.
Explorer 51, also called as AE-C, was a NASA scientific satellite belonging to series Atmosphere Explorer, being launched on 16 December 1973, at 06:18:00 UTC, from Vandenberg board a Delta 1900 launch vehicle.
Explorer 55, also called as AE-E, was a NASA scientific satellite belonging to series Atmosphere Explorer, being launched on 20 November 1975 from Cape Canaveral Air Force Station (CCAFS) board a Thor-Delta 2910 launch vehicle.
