Remote Bipolar Switch Circuit
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
A bipolar (set/reset) latch is actuated by a remote unipolar switch having no local power supply. A bipolar latch 1 is located at a distance from a unipolar switch 2. Switch 2, when closed, grounds the set input S of latch 1. An NPN transistor Q1 grounds the reset input R when switch 1 is open. Transistor Q1 drives its base current through a resistor R1 from the set line S which is pulled up by a resistor R2. When switch 1 closes, the base current is removed and transistor Q1 turns off, allowing the reset line R to rise. When switch 1 opens, the base current is restored to transistor Q1 and the reset line R is grounded.