1. A network filter usually consists of coils and capacitors, the very purpose of such filters (another name for EMI) is to eliminate (minimize) interference emitted to the network. In short, so that your TV does not "snow" at home when you connect such a power supply to the socket. 2. Bridge rectifier: https://pl.wikipedia.org/wiki/Mostek_Graetza 3. Capacitor C5 smoothes out the ripple caused by the bridge. 4. Tr is a transformer. But not the usual one used in typical power supplies, but a special one adapted to higher frequencies. Higher frequencies come from switching the transistor through the generator. The switching frequency may be, for example, several hundred kHz. (these are pulses, hence the name impulse) 5. Read about error amplifiers (a triangle with the letter W inside, plus and minus). 6. Isolation: read about optocouplers. By using such elements, you isolate one voltage from another. e.g. 230V from 12V. 7. Resistors R1 and R2 are voltage dividers.
1. A network filter usually consists of coils and capacitors, the very purpose of such filters (another name for EMI) is to eliminate (minimize) interference emitted to the network. In short, so that your TV does not "snow" at home when you connect such a power supply to the socket.
I disagree with the first one. EMI is an abbreviation for electromagnetic interference, not a filter name. At most it can be an EMI filter, but that means a filter against EMI interference. Element D1 is the so-called common mode choke, i.e. a filter against common-mode interference. Generally, this is not the time for such interference to cause snow on the TV, but it may cause other devices around it to work incorrectly, just like snow on TV receivers in the past.
A few more questions about power supplies: 1) What electronic devices can be a source of electrical noise or are sensitive to interference? 2) Are any protections used in power supplies?
1. All elements that are directly related to switching (keys, transformers, even poorly located paths may be a source of EMI), and sensitive ones may include, for example, microcontrollers, drivers, measurement systems. 2. This is how it is used, depending on what is being secured. The question is too general.
Very often, sources of interference are switching power supplies, especially cheap Chinese AC/DC converters. The same thing, on a slightly different note: engines. Of course, all kinds of filters are used, both on the 230V side of switching power supplies and within systems powered by such power supplies.
