A interesting question about use PC817 Optocoupler

Status
Not open for further replies.

thanhmssl10

Newbie level 5
Joined
Jan 1, 2015
Messages
9
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Visit site
Activity points
50
I think this problem is so interesting, I use PC817 like Datasheet, I connect pin 1 to a resistor 200 and a pin ( transmit PWM) from MCU, pin 2 to Ground, pin 3 to Power and a resistor 3K, pin 4 to Ground
Wow, it not work!

But If i add a diod to pin 1
It Work!
I Can't understand this problem because principle of Optocoupler is very simple, diod on and Transitor on, Have Any Answer for this problem?
 

Status
Not open for further replies.
Cookies are required to use this site. You must accept them to continue using the site. Learn more…