Surge protector, what it is and what it is
Surge protector (if we say, extremely easy) - it is an extension cord with a toggle switch. This element 99 cases out of 100 is used to connect to power stationary computer and its peripherals.
Additionally a filter is fed via a network and a plurality of other appliances. What's so special about this product and how it is so useful for devices and I'll discuss in this article.
Purpose mains filter
To begin with we shall understand what created a surge protector, and therefore begin a little distance. Because we all know very well that the voltage in your home network is 230 volts.
And it has a variable nature, which means that the voltage varies with time according to a certain law.
As you can see, stress has a sinusoidal shape. And exactly this kind would be in our outlets, if not a "but." Connected load not only draws power from the network, but also brings to the network, and something his, namely electromagnetic interference (switching power supply, capacitive and inductive load etc.).
And in reality, the supply voltage is as follows:
That such "ugly" sine wave and comes to us in the socket. A poor diet - it is undeniable problem for all radio transmitters.
So, a surge protector and serves to filter out interference to the normal (clean) supply electrical appliances, as well as to minimize interference produced devices.
The operating principle of a network filter
Filtering "garbage" signal components occurs special filters (pardon the tautology). Such filters are assembled from inductors and capacitors.
A probable from current surges use varistors. The filtering process is due to such processes as: a time constant and switching laws and reactance.
Interference high frequency
Thus, the high-frequency noise, had come from the network, designed to fight the inductance. All the matter in the reactive capacity of resistance. If the coil is supplied to a high frequency current, its resistance will increase continuously.
This inductive effect and allows you to cut a sine wave of small and large periods, these should could lead to high-frequency interference.
In addition, for maximum effect, apply once two coils that are placed on the phase and neutral conductor.
Low-frequency noise
Another problem associated with interference, having a low-pass character. To eliminate such interference have been used for coil resistance (resistors). The integrated surge protector pair of resistors rated at no more than 1 ohm increasingly used by 0.5 Ohm.
That is the main function of a network filter lies in the suppression of high and low frequency harmonics so that the output was close to perfect sine wave frequency of 50 Hertz.
What's inside a network filter
So, the principle of work and the appointment of this product seems to be clear. Now let's look at what is inside the expensive and cheap surge protector. Let's start with a rather expensive model.
As you can see, the filling of this product is quite rich. Here there is a full LC- filter. Zero and phase coils are connected to the inductance (each to his), and there is a block of capacitors.
Typical ratings in the following details:
1.Induktivnost coils - 50 200 uH
2. Capacitance of 0.22 to 1 uF.
Also present in the circuit varistor whose main task is to protect the product from the sharp increase in voltage. In most cases, use a varistor, rated at 470 volts.
Now, let's carefully examine the internal parts of the cheap filter.
As you can see from the diversity remained varistor, fuse and switch into the power strip. At its core, this is not a filter, and all but carrying with surge protection.
conclusion
Surge protectors - a product which is in every house. The only thing you know, buying a cheap copy of you get a simple power strip with surge protection function.
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