Elbatex SK

Elbatex SK and Measurement - why?

Measurement is one of the processes of learning the world around us. This process can be more or less successful depending on the openness of the environment being examined and the (non)existence of suitable measuring instruments.
Electrical measurement is very important and frequent. Its task is to get the values of stated electrical quantities as accurate as possible. One has to consider acceptable errors of measurement and to ensure that the measurement itself will not influence the measurement result. The errors of measurement are caused by many different factors that are not always avoidable. What can be still avoided is the use of improper instruments or methods caused by the lack of understanding of the object or process being measured and/or the principles of the particular measurement.
Our aim is not to cover all areas of measurement. We focus only on the measurement of the basic electrical quantities like voltage, current and different kinds of power and energy. These are important quantities of everyday professional life. We would like to offer to our customers appropriate instruments for correct measurement of abovementioned quantities.

Many people can measure a DC current correctly but only a few are able to do it if the current is an AC one.

What is the meaning of 1 volt or 1 ampere?

If we measure the voltage of a battery, the information obtained is quite unambiguous. If we use some ammeter to measure some current of an energy saving light bulb the readout means … sorry, I don't know. These pages should help to find the answer to this question.

Not only water and air but also the electrical current

Why all these problems with the measurement of AC voltage, current, power, etc.? Because we want to save energy. If we want a pleasant lighting we may lower the current by means of a transformer (or a resistor) - see the next figure. These methods however cause power losses and unwanted heat that must produced and be paid for. The "control" devices are not very cheap and small as well. (This is unpleasant.) The good news is that the current stayed sinusoidal. (Who cares?)

Another possibility is presented in the next figure. Simple electronic circuitry for some cents can adjust the brightness of the light almost without any power losses (This is superior). We simply "cut" a peace from the harmonic current. The bad news is that the current is devastated and contains a lot of higher harmonics. (Who cares?)

But this is not the end. The increasing number of electronic devices needs high-quality (energy-saving) DC power supplies. New electronic parts enabled us to develop switching DC power supplies according to the next figure and to produce them in high quantities.

Topswitch series circuit (producer Power Integration, distributor Elbatex SK)
1- Line rectifier, 2 - Small ferrite core, 3 - Output rectifier, 4 - Switching element

The AC input voltage is rectified. An appropriate switching component chops it with a high frequency. This enables the use of small and cheap ferrite transformers. Secondary voltage is rectified to the required DC voltage. A feedback loop controls the value of the output DC voltage by means of the width of the high frequency pulses (known as PWM).
The capacitor in the input part of the circuitry is periodically charged from the power network. This charging causes the input current in the form of narrow spikes. Can we measure the current of such kind of a load?

The yellow trace is the input current of a switching power supply,
red is the line voltage

This basic principle is used in PCs, TV receivers, battery chargers and many more applications - as good as everywhere. (Power saving is a superb thing.)

The pollution of electrical current is immense. Water can taste strangely; chemicals can be smelled in the air, but electrical current …? (Shouldn't we care?)

The instruments offered and delivered by Elbatex SK measure the electrical quantities correctly (within their specs) also when measuring real "ugly" waveforms existing in the practical life. "Nice" sinusoidal current waveforms are more and more rare.
We do not offer instruments with unknown meaning of their measurement results. Our portfolio is not wide, but our instruments will surely not disappoint you.

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