LED Annunciator OFF/DIM/BRT

This application diagram details a circuit that turns annunciators OFF/ON and also adjusts their brightness. The design provides dual user control and cycles through latched output states with the press of a momentary switch. The latched outputs can be used to control relays or toggle discrete dimming inputs to annunciators.

The design utilizes two switches, one with a VIVISUN Compact Body and the other with a VIVISUN High Capacity Body. The two bodies each house two momentary switch poles while the VIVISUN High Capacity Body also houses a NEXSYS Electronic Rotary (ER1) component. The ER1 controls individual annunciator states via latched outputs that are cycled through via successive switch presses

The ER1 powers up with output /Q1 (K2) low (ground) and outputs /Q2 (K2), /Q3 (K4) and /Q4 (J2) high-z (open). The LED (B) indicator is always illuminated. The low (ground) from output /Q1 (K2) controls the OFF state of the annunciators and illuminates the OFF (C) indicator. A press of either momentary switch passes a low (ground) through the normally open (A1 or H1) contact of the switch to input /INC (J3) of the ER1. This causes the ER1 to increment to the next latched state, and now output /Q2 (K3) is low (ground) and outputs /Q1 (K2), /Q3 (K4) and /Q4 (J2) are high-z (open). The low (ground) from output /Q2 (K3) controls the DIM state of the annunciators and illuminates the DIM (A) indicator. The OFF (C) indicator is no longer illuminated. Another press of either momentary switch passes a low (ground) through the normally open (A1 or H1) contact of the switch to input /INC (J3) of the ER1. This increments the ER1 again to the next latched state, and now output /Q3 (K4) is low (ground) and outputs /Q1 (K2), /Q2 (K3) and /Q4 (J2) are high-z (open). The low (ground) from output /Q3 (K4) controls the BRIGHT state of the annunciators and illuminates the BRT (D) indicator. The DIM (A) indicator is no longer illuminated. Another press of either momentary switch passes a low (ground) through the normally open (A1 or H1) contact of the switch to input /INC (J3) of the ER1. This causes the ER1 to increment to the next latch state, and now output /Q4 (J2) is low (ground) and outputs /Q1 (K2), /Q2 (K3) and /Q3 (K4) are high-z (open). The low (ground) from /Q4 (J2) is tied to input /RST (J1) of the ER1 and causes the ER1 to reset to the initial OFF state. The BRT (D) indicator turns off and the OFF (C) indicator is illuminated again.

Disclaimer: The configurations and diagrams shown above are provided by Applied Avionics, Inc. as a general example only. The recipient is solely responsible for actual design, electrical wiring, validation, testing, applicability and functionality of the product in regards to the customer’s specific application.