[SOLVED] 6n137 optocoupler testin

Status
Not open for further replies.
S

sabu31

Advanced Member level 1
Joined
Jan 28, 2011
Messages
467
Helped
12
Reputation
24
Reaction score
13
Trophy points
1,298
Activity points
5,359
6n137 optocoupler testing

Hi
I am trying to isolate microcontroller pwm from power circuit using 6n137 optocoupler. The circuit diagram is attached. When i am testing using function generator. I am not getting any output pulses. Vcc=5V, Function generator output 5V square wave , 50Khz. Function generator ground is seperate from Vcc ground.Could some one tell me whats wrong with circuit or how do i test the optcoupler. Thanks in Advance
 

Attachments

  • Drawing1.jpg
    14.8 KB · Views: 1,228

Pin7 (Ve) in the input to an NAND gate, you should connect it to 5v (High)
Pin6 (Vo) is the output but it is an open collector output, this actually means that the transistor can only ground the output or leave it floating
so to get a switching voltage you should connect a pullup resistor from Vo pin to the positive power supply (5v).
Check page 7,8 of the datasheet www.fairchildsemi.com/ds/6N/6N137.pdf

Alex
 
Reactions: sabu31

    S

    sabu31

    Points: 2
    Helpful Answer Positive Rating

Hi

I connected pull up resistor of 350 ohms.The circuit is working now. But still voltage output of pusles is of 3.5 Volts instead of 5 V (Vcc).
 

But still voltage output of pusles is of 3.5 Volts instead of 5 V (Vcc).
Click to expand...
Seems to indicate an additional output load, by specification of the part, the open collector leakage current is < 1 uA.
 

Hi

I am sorry, I could not understand by the "additional load". How do i isolate the problem.Thanks
 

Hi

The problem was that i had a driver IC connected to the opto which was loading the opto (as the driver IC was non powered).
 

Status
Not open for further replies.

Similar threads

Menu
Log in
Register
Cookies are required to use this site. You must accept them to continue using the site. Learn more…