Ok, first I want to thank everyone who replied to this... The responses make perfect sense, I picked the wrong part. I guess the next time I need to switch a light bulb, I'll be ready! Here is what I am trying to do. I have a shorting block I want to control from a PIC. I picked a relay since it's basically able to mimic a momentary pushbutton which is what I am trying to do. I assumed a "relay is a relay" so I thought a solid state relay would behave like any other relay, I was wrong! :) So basically I need some way to short a block momentarily, preferably without any additional hardware between it and the PIC (which is why I picked the previous relay, had 5V input, low low amperage to switch). Speed isn't a big issue, it needs to be able to switch on/off within ~500ms. If anyone can perhaps show me the "correct" solid state relay I would really appreciate it, as I don't want to just try again and see if I pick a DC one this time! :) Thanks again for all the answers! nick@veys.com | www.veys.com/nick > -----Original Message----- > From: pic microcontroller discussion list > [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Ned Seith > Sent: Thursday, August 02, 2001 4:12 AM > To: PICLIST@MITVMA.MIT.EDU > Subject: Re: [EE]: Solid state relay difficulty > > > Nick, > > The phototriac is intended to switch high voltage AC currents > from a low voltage DC source and to provide dielectric > isolation (7,500V insulation) between the DC and AC sources. > As per the pin out that you provided: Pin 3 is the anode of > the phototriac's internal LED. A DC current (+) of 10mA to 25 > mA should be applied to pin 3 to illuminate the internal LED > and to turn on the triac. Pin 4 is the cathode of the > phototriac's internal LED and is frequently connected to the > DC power supply's common (-). Pin 1 is typically connected to > the AC load. The other end of the AC load is connected > directly to the AC power source (excluding fuses/circuit > breakers). Pin 2 is connected to the AC common. A true test > of the triac's performance requires an AC power source, an AC > load and a low voltage DC power source. However, a crude > basic functional test may be performed using DC. While not > intended, nor conventional, the triac may be used for certain > DC applications, however, generally there are more > appropriate DC devices. > > Vasile, > > A triac will turn off or interrupt DC current, if the DC > current is pulsed energy and decreases in amplitude to near > zero volts. As an example, a triac will effectively control a > half wave or full wave rectified DC signal. However, an SCR > would be a more appropriate control device. > > Good Luck! > Sincerely, > Ned Seith > Nedtronics > 59 3rd Street > Gilroy, CA 95020 > (408) 842-0858 > > > > > At 09:22 AM 8/2/01 +0300, you wrote: > >It seems you don't know how a thyristor or a triac works. > >If you supply A-K ( thyristor ) or A1-A2 ( triac ) ( A = anode, K = > >cathode ) in DC the AK or A1-A2 junction will stay on after > a gate or > >opto command until the currrent through this junction will > go to zero ( > >in fact must be less than sustain current) and this will > never hapened > >in DC . Use a bulb for test and supply it in AC. Will works. Cheers, > >Vasile > > > > > >On Thu, 2 Aug 2001, Nick Veys wrote: > > > > > Hi all, I'm using an Omron G3MB-202P solid state relay, > 5V flavor. > > > It's a phototriac. It's not behaving how I would expect though, > > > hopefully someone can clear this up.. > > > > > > Pin definitions: > > > > > > 1 - load > > > 2 - load > > > 3 - (+) input > > > 4 - (-) input > > > > > > Here's what I am seeing: > > > > > > Connections: to test this I just want to light an LED... > > > > > > 5V to Anode of 5V LED > > > pin 1 - cathode of LED > > > pin 2 - ground > > > pin 3 - ground > > > pin 4 - ground > > > > > > This is how I start it up. > > > > > > Now when I apply power to this, of course nothing happens as I > > > expect. I then switch over the pin 3 to +5V, the LED lights, as > > > expected, I then switch the pin 3 back to ground, the led > stays lit. > > > In fact, no arrangement of the input pins (3,4) will make > the damn > > > LED shut off, I can't break the circuit once it's made... > Doesn't > > > sound too useful of a relay! > > > > > > Hopefully I'm doing something obviously wrong!! > > > > > > I've tried this with 3 different relays so I doubt they are > > > defective... > > > > > > Someone please smack me and tell me the simple solution! :) > > > > > > Thanks all! > > > > > > -- Nick > > > > > > nick@veys.com | www.veys.com/nick > > > > > > -- > > > http://www.piclist.com hint: The PICList is archived > three different > > > ways. See http://www.piclist.com/#archives for details. > > > > > > > > > >-- > >http://www.piclist.com hint: The PICList is archived three different > >ways. See http://www.piclist.com/#archives for details. > > -- > http://www.piclist.com hint: The PICList is archived three > different ways. See http://www.piclist.com/#archives for details. > > > -- http://www.piclist.com hint: The PICList is archived three different ways. See http://www.piclist.com/#archives for details.