what voltage to test this optocoupler?

Thread Starter

samsara

Joined Nov 19, 2022
2
Hi,
I'd like to test this optocoupler...
https://datasheetspdf.com/pdf-file/102011/TEMICSemiconductors/CNY74-4/1

using the method in this video...

However, I can't seem to find anywhere on the datasheet the voltage which I should apply from anode to cathode. according to one of the test diagrams 10mA of current (denoted as If ) should be enough but I'm confused as to the voltage.

If anyone could help me I would be very grateful
 

ericgibbs

Joined Jan 29, 2010
16,790
hi Sam,
Welcome to AAC.
You need a series resistor from the power supply, so that the current through the resistor and Opto Emitter is 10mA.
The forward voltage drop of the Emitter diode is approx 1.0V at 10mA
[1.25V at 50mA]

So depending upon the supply voltage choose a resistor value that gives a 10mA current, I have shown it for a 5V & 12V supply.
E
 

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