What is the idea of that diode?

Discussion in 'The Projects Forum' started by Edmunds, Jul 6, 2014.

  1. Edmunds

    Thread Starter Active Member

    Sep 27, 2010
    Dear Friends,

    I am creating a device that switches infrared signals from the device in the picture below on and off, thus sending model cars different commands at different places of the layout. I want to put the diodes in the picture on my own pcb, since I have several diodes run from the same PCB, I cannot really figure out where should they go and how many do I need. One per signal or one per signal/IR LED? Can anyone help me understand how they work and why they are there? From what I understand, the diode is a component letting current flow one way with some voltage drop and not in the other. How is that relevant for separating or perhaps merging the infrared signals into single IR LED in this case?

    Last edited: Jul 6, 2014
  2. wayneh


    Sep 9, 2010
    You're right about the properties of a diode. I believe in your application they prevent a "high" signal from driving current into a "low" signal. In other words the diodes allow you to "OR" the signals together without worrying about connecting them together and potentially getting a damaging current to flow. When properly "OR"ed together, a high on any of them produces a high on the combined output.