Connect with us

EMITTER DETECTOR SENSOR

Discussion in 'Sensors and Actuators' started by BHEKI, Nov 10, 2014.

  1. KrisBlueNZ

    KrisBlueNZ Sadly passed away in 2015

    8,393
    1,266
    Nov 28, 2011
    You should run the IR LED at the current recommended in the data sheet. If in doubt, try 20 mA. IR LEDs have a forward voltage of around 1V so calculate your series resistor using Ohm's Law to give the desired current with (power supply voltage minus 1 volt) across it. For example if your power supply is 12V and you want 20 mA to flow, calculations would be:

    R = V / I
    = (12 - 1) / 0.02
    = 11 / 0.02
    = 550Ω.
    Closest preferred value is 560Ω.

    Yes you can use any small-signal PNP Darlington transistor, or you can connect two small-signal PNP transistors (e.g. 2N3906) together in a Darlington connection (see https://en.wikipedia.org/wiki/Darlington_transistor)
     
  2. BHEKI

    BHEKI

    24
    1
    Aug 28, 2014

    Thank you for this information,im grateful
     
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day

-