Photodiode

[rockandroll]

Hi ,

I am having problem about the Photodiode.

I don't know how to operate a set of "Transmitter LED" and  "Receiver Photodiode". Is it possible in Multisim ?

I think photodiode symbol has its arrow pointing towards it But in Multisim the arrow point is just opposite.

Desperate for your co-operation..

Regards,

[Tien_P]

Hi,

Multisim doesn't have a photodiode, the one found in the "Rated" family was incorrectly called photodiode but it's a LED.  That component was intended to work with the Phototransistor from the same family, when the diode turns on the transistor can detect it.  Attached is an example how the two components work together.

Beside the Phototransistor I mentioned above, Multisim doesn't have any component that detects light.  What you can use instead is a Voltage_Control_Voltage_source from the "Sources" family.  The light input can be emulated with a voltage source, 

[_user32]

rockandroll,

Here is another example showing an equivalent model for a photodiode with a log amp (AD8304).  The schematic was created to mimic the related log amp evaluation board (thus the 100MOhm (open) and 0Ohm (short) jumper resistors).

In this case an interactive potentiometer controls the current going through the photodiode allowing the user to adjust.  

See the Analog Devices whitepaper (the link is inside the schematic) to learn more.

Regards,

Pat

[rockandroll]

Hi,

Can I use the suitable 'Opto-Coupler' for 'Photodiode' ???

rockandroll.