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Two pin IR reciver LED configuration [SOLVED]

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amir.razzaqi:
 :palm: :palm: :palm:Hello
I want to see IR remotes carier signal using single two pin IR reciver diode connected to osciloscope. How to config this diode on breadboard and what voltage do I use?
I appreiciate any help or schematic circuit

Zero999:
Connect the diode in reverse series with the power supply, with a resistor to 0V.

http://electron6.phys.utk.edu/optics421/modules/m4/detectors.htm

amir.razzaqi:

--- Quote from: Zero999 on September 03, 2023, 09:09:32 pm ---Connect the diode in reverse series with the power supply, with a resistor to 0V.

http://electron6.phys.utk.edu/optics421/modules/m4/detectors.htm

--- End quote ---

I use 2 different possible configuration according to the attached photo. by aiming TV remote to the IR receiver, scope in first config show continuous +5V and in the second config show fix 0 Volt. it does not react to IR light emitted from TV remote completely.

Ian.M:
The photodiode in photovoltaic (zero bias) mode will react to the RC modulation envelope if connected directly across the scope input (DC coupled) with no other parts, if the IR illumination is strong enough.  It wont be fast enough to resolve the typ. 38KHz carrier.   You need to get the remote's IR LED within a couple of cm of the photodiode, and shield the photodiode from direct room lighting - a few cm of black rubber tubing is ideal.   

When I used to work in a TV shop, we kept a BNC connector with a photodiode connected as described, permanently on one of our scope channels, only removing it if we needed all channels for a particular job.

To resolve the carrier, you'd need to run the diode in photoconductive (reverse biassed) mode and minimise the effect of the photodiode's junction capacitance, which would probably require a transimpedance amplifier.  Due to varying ambient lighting you'll probably need to servo the bias voltage to keep the output between the rails.

amir.razzaqi:

--- Quote from: Ian.M on September 04, 2023, 07:00:46 am ---The photodiode in photovoltaic (zero bias) mode will react to the RC modulation envelope if connected directly across the scope input with no other parts, if the IR illumination is strong enough.  It wont be fast enough to resolve the typ. 38KHz carrier.   You need to get the remote's IR LED within a couple of cm of the photodiode, and shield the photodiode from direct room lighting - a few cm of black rubber tubing is ideal.   

When I used to work in a TV shop, we kept a BNC connector with a photodiode connected as described, permanently on one of our scope channels, only removing it if we needed all channels for a particular job.

To resolve the carrier, you'd need to run the diode in photoconductive (reverse biassed) mode and minimise the effect of the photodiode's junction capacitance, which would probably require a transimpedance amplifier.  Due to varying ambient lighting you'll probably need to servo the bias voltage to keep the output between the rails.

--- End quote ---

does IR receiver Diode has photovoltaic feature?

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