The rear lights of a car are to be controlled by digital logic

Thread Starter


Joined Feb 20, 2017
The rear lights of a car are to be controlled by digital logic. There is a single lamp in each of the rear lights.

The inputs are:
  • -LT left turn switch — causes blinking of left side lamp
  • -RT right turn switch — causes blinking of right side lamp
  • -EM emergency flasher switch — causes blinking of both lamps
  • -BR brake applied switch — causes both lamps to be on
  • -BL blinking signal with 1 Hz frequency
The outputs are:
  • -LR power control for left rear lamp
  • -RR power control for right rear lamp
Implement each function LR (BL, BR, EM, LT) and RR (BL, BR, EM, RT) with a 4-to-16-line decoder and external OR gates.


Joined Mar 14, 2008
You have not asked for what you want (other than the obvious for us to solve the problem for you).
This is a Homework Help, not Homework Do forum.

What's your approach to solving the problem?
Have you studied the 4-to-16-line decoder to understand how it works?


Joined Nov 13, 2010
Here is an example of using a decoder to solve the brake light problem; however, the design parameters are far outside the original instructions which require use of two 4-to-16 line decoders plus some external OR gates. This solution uses a single 3-to-8 line decoder plus some OR gates. Logisim circuit file attached for anyone who may want to run the simulation.