Electrometer, what is it and how to choose the best one?

November 2, 2021

The electrometer is a laboratory material that is used to evaluate the presence of charge that can be used in a certain object. An electrometer is generally made of a conductive material, such as metal, so that charge can flow freely over a conductor. And, if the load occurs at a particular point, it will be gradually distributed on the surface of the conductor.

An electrometer has a rotating arm that indicates the net presence of a charge. In general terms, and easier to explain, the laboratory instrument is capable of detecting the presence of a charge or ionizing radiation. Which consists of a pair of thin gold sheets that are suspended by an electrical conductor that leads the load to the outside. All this through an insulating container.

In the case of the electric charge flowing through the electrometer, it is carried close to the conductor, or is in contact with it so that the sheets are kept apart at an angle. This obeys the coulomb’s law, which indicates that the electric charge is similar once it is induced or transferred to each sheet in order to repel each other.

The radiation of the materials, which by duty should indicate how radioactive they are, and are introduced into the electrometer, are charged with gas ions inside. This allows the load to gradually filter out and fulfill the function of the laboratory tool . The speed at which the sheets are charged in the electrometer converges to their parallel position without charge, which is proportional to the radiation.

Next, we will break down in detail a laboratory instrument that is well known in the area of ​​physics to study the behavior of a spectrum as important as electricity. Together with the dynamometer , they fulfill specific functions in the physical field. You want to know more? Join us!

What is an electrometer?

When we talk about the electrometer, we refer to an instrument of a scientific brand that was, and is used, to detect the electrical charge present in a given body. The material detects the charge thanks to the movement of the object under test due to the electrostatic force on it. In the case of the amount of charge that is exerted on the object, this must be proportional to the voltage or it would not be fulfilling the laws of coulomb.

To detect a sufficient charge in the body, it is necessary to measure its accumulation in an electrometer. But, for this to happen, it takes hundreds, and even thousands of volts. This only indicates that the electrometer works with high degrees of voltage sources. The above is complemented with the quality that the electrometer must have, since if it is not capable of withstanding the voltage sources, it will not achieve adequate results. The fonts that apply to the lab tool are:

  • Static electricity
  • Electrostatic machines

The amount of charge indicated by an electrometer is only an approximation, so when it comes to precision, it is not something that was taken 100%. And, for what you are a little confused about the quantitative of an electrical charge in a body, another type of laboratory material is used, which is called an electrometer.

History of the electrometer

The first electrometer created is awarded to the British William Gilbert , and the date dates back to the year 1600. In fact, this great and very simple material that is used today in the laboratory, was the first electrical measuring instrument that the world knew. . This contained a pivoted needle, which had the name of versorio.

After years of improvement, the gold leaf and marrow ball electrometer were created, which are two classic types of the measurement instrument named above. These are still taught in physics classes and school labs to demonstrate to newcomers how electrostatics works.

This instrument has had a great impact in history, in fact, the scientist Victor Hess used it in the discovery of cosmic rays. An electrometer has also been used in the quartz fiber radiation dosimeter. So it has gained popularity in what we scientifically speak.

Electrometer overview

The electrometer contains a conductive sphere together with a metallic rod that is attached to the mentioned sphere. The gold leaves, which are located at the bottom of the bar, must be firm and working at all times. For that is where the catalyst principle works. The amount of distance between the blades will depend on the amount of charge on the instrument.

In general, electrometers come with a glass box in order to reduce the ions in the air and the damage caused by the effects of the wind. Some of these are neutral, but if charged, because they repel each other, the instrument blades will rise.

How safe is the electrometer?

Actually, the electrometer is one of the instruments used for the safest experiments. Although it is being handled with electricity, the results are usually quite weak and unimpressive, unless a high amount of voltage is exerted on it.

Uses of the electrometer

Throughout the article, a number of uses have been named , but among the general ones, and for which it was created, they include the following uses:

  • It is used to detect the static charges of a body
  • The nature of electric charges can be determined using an electrometer
  • In addition to determining the nature, you can compare the magnitudes of two charges once you use the electrometer.

How does the electrometer work?

There is a certain principle on which the operation of the electrometer is based and one of them is the atomic structure of the elements. The other is the induction of the load, combined with the internal structure of the metallic elements. The idea behind this operation is that the charges are similar and manage to repel each other. However, if they are not similar, the must be that they attract each other.

When there is no load, the metal sheets hang down . But if the laboratory instrument is loaded, two specific things can happen. The first is that the positive charge and the electrons in the metal of the tool attract each other. Causing the leaves to tip upwards. When the charge is removed, the electrons return to their original position.

The second, and it is in case that the charge in the electrometer is negative, the electrons in the metal of the laboratory instrument repel each other and move upwards. The leaves will generate a negative, temporary charge. Then once the load is removed, the same will happen as in the last principle. The electrons will return to their original state and the leaves will repel each other.

The electrometer always responds to charge because it is present through the movement of electrons. Either inside outside the sheets that it has incorporated. You need to know that when the electrometer cannot determine whether the charge is positive or negative, it only responds when it encounters an electrical charge. Which is the principle that has been mentioned.

Electrometer types

Marrow ball electrometer.

The creation of this instrument is attributed to John Carton , while the date on which he registered his idea was in the year 1754. The premise of this type of electrometer consists of one, or two, small balls of light charged with a non-conductive substance called marrow. The function is for the tool to determine whether the balls are loaded or not. To do this, it must be brought close to the unloaded cord. In the event that the balls are attracted to the object in question, this will only confirm that it is charged.

Gold Leaf Electrometer

In the case of this type of electrometer, it is credited with the creation of Abraham Bennert , who developed the instrument in 1787 and called it ‘gold leaf’. Generally speaking, it is usually more sensitive than the type described above. The description of this electrometer consists of a vertical rod that is metallic and has two parallel strips. And, with a thin, flexible gold leaf dangling from it. To prevent the gold leaf from leaking air, it must be stored in a very secure glass bottle. The leaves for which it bears its name separate in an inverted ‘V’ shape, once the loaded object is approached.

Electrometer example

An example of this type of instrument may be that a negative charge is used. If the distances between the electrometer and the conductive plates are equal, the types of charges must be found. If there are no changes in the behavior of the sheets, the effect of the plate must be canceled with the other plate.

In the event that the blades close a little, then some of the electrons in the blades must move to the top of the electrometer. And lastly, if the leaves are raised, even a little bit, then some of the electrons on top are moving towards the leaves because they are negatively charged.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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