I am trying to close a relay using an opto interrupter. I have it working to the point where I have an LED becoming unlit when the opto interrupters' beam is broken. I have tried many circuits for amplifying the signal with no luck. Can someone please post a simple circuit for activating a relay? Have 3409 and 2N2222 transistors and 555 iC.
Thanks,
Jim

 

What slot Opto are you using? and what is the current rating of the relay? What supply voltage are you using for opto and relay?
Using a typical slot opto it should be a trivial matter to either use the emitter or collector side of the opto output or amplify it with the 2n2222 or use a 2n7000.
Max.

 

I am using 5v but could go higher if it helps. I have relays rated at 6 volt coil and also some rated at 4.5 volts.
Yes, it should be trivial, and I've tried multiple circuits that I got off the web, and also feeding the detector side higher voltages. The opto interrupter is part # QTC 9536, but I would be happy using individual components. Any help would be much appreciated. A schematic would be ideal with parts values, etc.
Thank you!!
Jim

 

Couldn't see anything on the QTC9536? Do you have a link to the data sheet?
The diode side you select a resistor based on the spec sheet current and your applied voltage.
Max.

 

The marking on the opto interrupter is Qtc9536 H21A2

I have selected a good resistor to lower the voltage to about 3volts (330 ohm) on the diode side.

The transistor your recommend is TIP120. I don't have this part. Would 2n2905 suffice? 2n2222, or 3904? Also have to-220 ab mosfet.

I see you went to 24 volts on the transistor side. Is the neccesary when using a 6vdc coil relay?


Thanks,
Jim

 

Something like this.
Max.

 

Thanks Max,
I had it working, and then somehow blew out the infrared led, so everything's on hold till I get more parts. I'm going to order the exact parts you specified so there are no problems. I'll let you know how it works out!
Thanks again,
Jim