use of a optoisolator in a power supply 4N35 fairchild

Hi to all,

I've read over some of the similar posts...but no help. I'm building a micro controller on a proto-board, for use on a power line carrier set up. I have a schematic that shows (as part of a 120vac to 5v power supply) two leads from the step down 120v-9v transformer (there is also a voltage reulator 7805) going to the ac inputs of bridge rectifier as well as the to pins 1 & 2 of the 4N35nd to pins shows, so far so good, I get it.

It also shows pin 4 to GND, but pin 5 is labled as going to 60Hz. The designer is no longer accessible. Any suggestions? I've attached a portion of the schematic

The only connection made to the 4N35 thus far is pin 4 to GND, the rest of the system works ok so far...obviously want this crucial part ot be functional as well.

thanks...optomist1

Everything's fine with the schematic. Obviously, this circuit is used for a synchronization purpose. Pin5 should be connected to +5V (or the positive rail) by a pull-up resistor. The "60Hz" labeled rail, in this case should be considered as an output rail. On that same rail, if observed with scope, the signal should be rectangular with F=60Hz, period ~16,67ms(for 60Hz mains), and Duty_cycle= ~50%. The "60Hz"-rail is probably connected to the microcontroller, which is using the signal for synchronizing with the mains voltage and is commonly used for switching or phase regulating of AC loads with triacs.

teodor,

many thanks...I thought thats were it belonged, and yes the 60 Hz is connected to the micro.

this is a great site....as I wade through getting this project up and running.

Regards,
Marty