What is an electric tester? Working principle? How to use an electric tester?

Electrical testers are common household handheld devices. However, many people still do not know what an electric tester is, should buy an electric tester or a good electric tester. So let’s refer to this article with Tnhelearning.edu.vn to understand better!

What is an electric tester?

The electric tester is a common tool to quickly check before repairing the device for leakage, or whether the plug in the house is live or not.

Electrical tester is used to quickly check whether electrical equipment is leaking or not

Types of electric tester pen:

• Electrical tester with contact with electricity: This is a type of electric tester that uses the parasitic capacitive effect on the human body to work. The electric tester in contact with the mains is also the most original, appeared on the market very early and is commonly used in many families.
• Non-contact electric stylus: Unlike the above type, the structure of this electric tester is quite special. It works based on the phenomenon of electromagnetic induction of current to check the presence of current. The non-contact electrolytic tester can detect this magnetic field current and notify via the indicator light at the tip of the pen.

Internal structure of the electric tester

The internal structure of the electric tester consists of a metal body in direct contact with the power source. Next is the resistor connected directly to the neon bulb, the conductive spring and finally the metal tip. The outer shell of the electric tester is made of specialized plastic with very good electrical insulation, protecting the user’s life during working with electrical equipment or live objects.

In addition, the clamp of the tester is used to hang or guide the pen to a rack or place. The metal pen cap is used on the top of the handle to open when the pen has a problem. The handle cover is made of insulating plastic, ensuring safe use.

Detailed structure of the internal parts of the electric tester

How to use an electric tester

We put a pen tip into the circuit to be measured, our finger placed in contact with the metal tip above the tip of the pen. If the circuit is energized, the neon bulb element on the pen will light up.

How to use a simple electric tester

Working principle of electric tester

The low voltage tester uses the parasitic capacitive effect on the human body to make it work.

When the tip of the pen is placed on a live object, the current will pass through the resistor , through the bulb, and through the capacitance of the human body to form a closed circuit, causing the bulb to light up . Normally, this current is so small that it is not enough to cause a fatal shock.

Red neon light, when the device to be checked is current

How to use electric tester safely

Use an electric tester to check the AC power line

The electric tester glows because when you put the pen into one of the 2 pins , if it’s a hot wire, the tester will light up, if it’s a cold wire , the light won’t light up.

Use an electrical tester to check the AC power cord

If the lights in the electric tester are all lit when the electric tester is in contact with the phase or neutral wire , then there is a problem with the power source, the power must be checked immediately to avoid danger when using electricity. Since the neutral wire (neutral wire) is a non-electrified wire, the tester will not light up.

Use an electric tester to distinguish AC from DC

When the neon lamp of the electric tester is energized , only the pole connected to the cathode of the DC source will glow .

When tested with AC source, the two poles of the neon bulb alternate as +/- poles , so both poles glow. When connecting a tester to the positive (+) and negative (-) poles of a DC circuit, only the pole connected to the (-) pole of the power source will glow .

The electric tester can distinguish between AC and DC power

Use an electric tester to distinguish the electrode of a DC source

When connecting the electric tester to the positive (+) and negative (-) poles of a DC circuit, only the pole connected to the (-) pole of the power source will glow.

Tolsen 38114 140 mm electrical tester for electrode discrimination of DC power

Note when using:

• The pen will not be used to test direct current (DC) voltage.
• Because the electric tester uses parasitic capacitance on the human body to conduct electricity, the pen will cause a shock if the bulb inside or the resistor is touched (due to water getting inside the pen).

Hopefully, the above information will help you use the electric tester safely and effectively! Please leave a comment if you have any questions for Tnhelearning.edu.vn!