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Multi-Status Indicator Using Single RGB LED Schematic Circuit Diagram

In monitoring systems like those found in battery chargers and water-level indicators, LEDs are frequently employed to signal specific conditions. Here, we introduce a multi-status indicator circuit that utilizes a single RGB LED to convey seven distinct indications.

Circuit and work for Multiple Status Indicator Using Single RGB LED

A circuit diagram of the multiple status indicators using a single RGB LED is shown in Fig. 1. It is built around priority encoder CD4532 (IC1), common-cathode RGB LED (RGB1), and a few other components. IC CD4532 is an 8-to-3 priority encoder that converts 8-bit data inputs (D0 through D7) into 3-bit binary data (Q0 through Q2).

Fig. 1 Circuit diagram of multiple status indicator using a single RGB LED

The RGB LED is linked to the binary output of IC1. Whenever IC1 produces a high output (5V) at data pins Q0 through Q2, the LED generates various colors corresponding to different data sequences outlined in the table. To control the current flowing through the LED and to avoid excessive current, individual resistors R1 through R3 are employed for each color. This setup enables the RGB LED to display up to seven distinct states, each represented by a unique color, as detailed in the table.

Circuit diagram of multiple status indicator using a single RGB LED

Construction and testing

 An actual-size PCB layout of the multi-status indicator using a single RGB LED is shown in Fig. 2 and the layout of its components in Fig. 3.
Fig. 2: Actual-size PCB of the multiple-status indicator using a single RGB LED
Fig. 3 Components layout for the PCB
This circuit can be operated using either a 6V battery or a stabilized 6V DC source. Various combinations of high (5V) and low (0V) inputs are applied to IC1’s digital input through CON1, as indicated in the table. The circuit can be enclosed within a compact plastic enclosure. If needed, additional ICs can be cascaded with IC1 to accommodate more inputs.
Multi-Status Indicator Using Single RGB LED

Features of CD4532 :-

  • Converts from 1 of 8 to binary
  • Provides cascading feature to handle any number of inputs
  • Group select indicates one or more priority inputs
  • Standardized, symmetrical output characteristics
  • 100% tested for quiescent current at 20 V
  • The maximum input current of 1 µA at 18 V over full package temperature range; 100 nA at 18 V and 25°C
  • Noise margin (full package-temperature range):
    0.5 V at VDD = 5 V
    1.5 V at VDD = 10 V
    1.5 V at VDD = 15 V
  • 5-V, 10-V, and 15-V parametric ratings
  • Meets all requirements of JEDEC Tentative Standard No. 13B, “Standard Specifications for Description of ‘B’ Series CMOS Devices”
  • Applications:
    • Priority encoder
    • Binary or BCD encoder (keyboard encoding)
    • Floating point arithmetic

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