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rMDservice manual download site
(7) maintain and information transmission circuit made up of transistor Q857 and peripheral components. Protect tube Q856, optical coupling D819 conduction and shut down after the main power grid, power no voltage output, triode Q856, optical coupling D819 lose conduction voltage at the same time, also can't maintain protection state, must through the microprocessor to execute commands on standby, can maintain the protection state unchanged. In the triode Q856, optical coupling D819 perform protection and close the main power supply at the same time, not only pull Q852 base voltage is low, also by R856 and R858 pull PNP transistor Q857's base potential is low, cause Q857 conduction, the conduction of collector electricity of subsection two after the road: all the way through to the microprocessor R865 into high level 6 foot, will protect the information transmitted to the microprocessor, the microprocessor from on to standby mode, accordingly from the output low level 33 feet standby control voltage; The other all the way through R859, D859 offer Q856 forward voltage, maintaining the instantaneous protection state protection of information transfer. rMDservice manual download site
rMDservice manual download site
(8) IC801 internal protection circuit. Thick film circuit switch power supply IC801 inside also has a perfect through the voltage protection circuit, such as IC801 power 5 feet internal overvoltage protection function, when the normal 5 feet of voltage between 15 ~ 16. When the mains voltage is too high or switch power supply output voltage is too high, the input to IC801 5 feet voltage also rise. When the voltage is greater than 5 foot 28 v, 5 feet internal protection circuit action, IC801 vibration. R809, IC801 R810 for internal power tube flow measuring resistance; When load current is normal, minimal pressure drop on the R809, R810, impact on circuit is not; Once the load increase, its voltage drop increases, the voltage by R811 added to IC8014 feet, make the internal protection circuit action, IC801 vibration.
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