Abstract: A simple circuit employs a small transformer and latched comparator to sense the state of a digital line without drawing power from the line. Maxim > App Notes > Amplifier and Comparator Circuits Keywords: galvanic isolation, digital state detection, single-turn transformer Mar 23, 2005 APPLICATION NOTE 3473 Read Isolated Digital States Without Power Drain Abstract:A simple circuit employs a small transformer and latched comparator to sense the state of a digital line without drawing power from the line. A similar version of this article appeared in the November 25, 2004 issue of EDN magazine. Electronic systems must often isolate their inputs or outputs from the main reference common (ground). Various conditions can make necessary such galvanic isolation: the type of input sensor or driven actuator, safety considerations for medical equipment attached……