question about ir leds (sender-receiver)

Hello every one!

i want to ask a question, is an ir led receiver like an ir led sender, but only in each configuration the ir led does its role?!

plz also tell me what's the simplest configuration to design ir sender-receiver electronic circuit sensing if the ir level is over or less a predefined threshold level?!

Thanks in advance!

antoine magdi said:

Hello every one!

i want to ask a question, is an ir led receiver like an ir led sender, but only in each configuration the ir led does its role?! [/U][/B]

Click to expand...

Can you please reword the question in a few more different ways? I don't understand what you are trying to say.

what's the difference between ir led sender & ir receiver?!

One transmits, the other receives...

An IR transmitter uses an LED to send light. An IR receiver is a photo-diode or photo-transistor that is activated by IR light. A photo-diode is like a diode a normal diode that works better and produces current when light is shined on it . A photo-transistor is like a transistor where the base/gate is driven by light rather than electricity.

Something like this circuit might work. It's very simple and easy to understand, but I don't think it would work very well.

sorry, but if the ir receiver (photo-diode for example) produce a voltage when light is shined on it; why i wire up it with a power supply and make a voltage divider?!!

Really thanks for helping me, and for your full explanation! thanks a lot!

The photo-diode circuit is wrong. The photo-diode can be reverse-biased with a voltage then light cause it to conduct a little.

A photo-diode can generate a current like a solar cell then it does not need a reverse voltage but its generated voltage is very small and needs an amplifier in order to frrd the comparator.

Most comparators need a pullup resistor at the output.