Computer RS-23Z serial interface current loop circuit

Published:2011/4/10 21:14:00 Author:Nicole | Keyword: computer, serial interface, current loop | From:SeekIC

This circuit is used in computer RS-232 serial interface and current loop circuit interface, it can transform voltage singal into 20mA current singal, the maximum transmission rate is 1200 bits. CCD IC1, T1 form receiver interface circuit, T2, T3 constitute transmitter interface circuit. When adds +12V, T2, T3 are conduction, the current outflows from T2 collector, and pass along the line then reach the ① of IC1, though LED of IC1, and pass along the line again then return to transmitter, the loop current is about 20mA. When adds -12V, T2, T3 cut off, there is no current in circuit. When current flows IC1 transmitter, the receiver is conduction, T1 is conduction, T1 collector sends out +12V electrical signal, when T1 cuts off, -12V electrical signal is sent to RS-232 through R4. Then to achieve use current loop to transmit digital signal.



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