A few days back I had a chance to work on an IR transmitter/receiver circuit. It was long time since I was engaged in a real circuit design. Most of the previous time I spent was on PCB design and firmware development. The TX part worked like a charm but when the RX part came I really found problems reducing the noise at the input. This noise caused to trigger a false alarm and hence crippled the very purpose of circuit. This led me to look into the very physics of optical sensor. First, I read through the data sheet, which revealed that it is a PIN IR junction diode. Then I further dug into the PIN junction and this recalled me that no biasing voltage is required for it as it generates its own sufficient potential to feed into an amplifier. This reminded me the days of my solid state electronics courses at college and university. This was the subject I really liked because of interesting concepts of semiconductor Physics. I redesigned the whole circuit and it really improved the performance. This made me think that electronics engineers must not forget those Physics lessons back in college and university which we often do due to much brainstorming in the application development.
