EMITTER DETECTOR SENSOR

[KrisBlueNZ]

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)

 

[BHEKI]

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)

Thank you for this information,im grateful