4N35 optocoupler issue

Thread Starter

kaning

Joined Jun 2, 2014
43
I want to use optocoupler 4N35 as switch to turn on a 5v fan.
im using generic design of led input 5v in series with 1k resistor.
i turn on led with 5v and i get reading of 5v on the other but when i connect the fan to the 5v on the other side i get only 2,3v... why such a big drop? internal resistance?

i would apreciate some help, thnks in advance.
 

Thread Starter

kaning

Joined Jun 2, 2014
43
i used a transistor (bc457), where its base was fed by the optocoupler, collector with 5v and fan on emitter to ground and now everything is ok and working...
 
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