Electrical measurements are very accurate, reliable, simple and cheap. Therefore, electrical meters have been widely used in the measurement of non-electrical quantities.
The electrical system that measures non-electrical quantities includes the main components, such as: a sensor (transducer), intermediate devices and an indicator.
Electrical measurements of non-electrical quantities are essentially a sensor’s conversion of a non-electrical quantity, say, a change in liquid level, speed, temperature, etc., into a change in electrical quantities: resistance, voltage or current, measured by an indicator, which is a simple electrical measuring device.
Devices used for electrical measurements are divided into two categories:
- analog ("tseshki") - in them the measurement result on the scale of the device shows the arrow;
- digital - in them, an analog-to-digital converter converts the input signal to digital and displays its value on the LCD.
Today, digital devices have replaced analog, one might say, completely, because, first of all:
- they are easy to use (unlike analog (arrow), they have no such concepts as measurement limits or graduation of the scale of the device, which must be understood);
- they are much more accurate than analog ones.
The following advantage of such devices should be noted: electrical measurements allow testing non-electric quantities even in hard-to-reach places or at a considerable distance.
Let's look at two specific examples of how to conduct electrical measurements using devices that measure non-electrical quantities.
Wood moisture meter
Since wood is a hygroscopic material, with a change in the parameters of the environment, its humidity changes - one of those properties of wood that are so important when it is used in finished products. Therefore, the wood is dried to a uniform state, taking into account future operating conditions.
One of the methods for measuring its moisture is the use of electro-moisture meters . The principle of operation of a moisture meter is to measure humidity, which is based on electrical properties. Using the device, you can quickly determine it without destroying the wood.
Hydrometers are of two types:
- needle - they are based on the measurement of electrical resistance;
- capacitive (non-contact) - they are based on the relationship between permittivity and humidity. These moisture meters have sensors that do not require the introduction of needles into the wood. Therefore, there are no traces left on the surface of the wood after measurements, which, of course, compares them favorably in this regard from needle hydrometers.
Nitrate meter
Nitrates are one of those chemical compounds that are most dangerous because they can become a source of serious disorders in the human body. Once in large quantities with food in the human body, they can cause nitrate poisoning, various chronic diseases and disorders.
The once laborious and expensive process of detecting nitrates is currently carried out by a small special device - nitratomer.
Nitratomers are designed to measure nitrate content in fruits, vegetables, and fresh meat. The basis of their work is the measurement of ion activity by the electrode system in a direct potentiometric manner, the results of which are converted into an electrical signal in proportion to the concentration of NO3 ions.
To determine and measure nitrates by pricking the product, a special contact probe (probe) is provided in the device.
Nitratomer is a digital device. Its measurements are displayed on a convenient color display.