电气隔离（Electrical isolation）.doc

电气隔离（Electrical isolation） The introduction The main purpose of circuit isolation is to cut off the noise interference through the isolation component, so as to suppress the noise interference. After adopting the circuit isolation measures, most of the circuits can achieve good suppression of noise, so that the equipment meets the requirements of electromagnetic compatibility. Circuit isolation is mainly: the isolation of analog circuits, the isolation of digital circuits, the isolation between digital circuits and analog circuits. The isolation methods are used: transformer isolation method, pulse transformer isolation method, relay isolation method, photoelectric coupler isolation method, dc voltage isolation method, isolation method of linear isolated amplifier, optical fiber isolation method, A/D converter isolation method, etc. The isolation of digital circuit is mainly: pulse transformer isolation, relay isolation, photoelectric coupler isolation, optical fiber isolation, etc. The digital input isolation mode mainly USES pulse transformer isolation and photoelectric coupler isolation. Digital output isolation method is mainly used in isolation of photoelectric coupler, relay isolation and high frequency transformer isolation (in individual cases). The isolation of analog circuit is more complicated, depending on the accuracy of the transmission channel, the higher the accuracy requirement, the higher the cost of the channel. However, when the requirements of performance rise to the main contradiction, the separation components should be chosen as the main performance, and the cost will be placed second. On the contrary, it is necessary to choose the isolated component from the Angle of price. The isolation of analog circuit mainly USES transformer isolation, transformer isolation, dc voltage isolator isolation and isolation of linear isolation amplifier. The separation between analog circuit and digital circuit is mainly used in mode/number conversion device.