hopefully a picture. 5 lines going to the comparator. posative, negative, and output. where do the other 2 lines hook to the comparator when looking at the comparator 14 pin diagram?
hopefully a picture. 5 lines going to the comparator. posative, negative, and output. where do the other 2 lines hook to the comparator when looking at the comparator 14 pin diagram?
If it's an LM339, there are 3 unused sections. You can connect one input of each section to ground so that they don't oscillate internally, or affect the internal biasing of the one you are using. Look at the datasheet to see which pins the inputs are on.
EDIT: Corey posted the pinout while I was composing my reply.
Thankyou all. thats what I was asking. So how do you know where the power will come out with 4 output pins? Pins 1, 2, 13, and 14? which one do I wire to my relay?
The LM339 is a quad comparator, meaning there are four comparators in one package. Apply power to pins 3 and 12. If you only need one comparator, then use only one. Pick one! Once you've done that, then follow Ron's advice above, i.e. ground one input of each of the comparators not in use.
hopefully a picture. 5 lines going to the comparator. posative, negative, and output. where do the other 2 lines hook to the comparator when looking at the comparator 14 pin diagram?
Perhaps what's confusing the OP is the fact that the comparator as used in the circuit is sinking current through the LED. He is probably expecting a wire to go to his relay as it would in a sourcing arrangement.
All that is necessary for him to do is replace the led in the circuit with his relay, and a suitable reversed parallel diode.
The LM339 is a low power quad comparator. The LM393 is the same but it is a dual comparator in an 8-pins package.
Because they are low power, their minimum output current is only 6mA (with a saturation voltage loss of up to 1.5V) which is too low to drive most relays.
Sorry about that guys. I was trying to upload a thumbnail and was having lots of trouble getting it done. (still on dial-up). As well, this stuff is quite a ways above my head so thankyou for your patience. I believe I now have enough info. to start building. Hopefully it will work. I hunted for quite some time to find relays with the lowest coil voltage possible.(5v, 69.4ohm,spst relay) Thankyou all for your input.
I've been tryinig to improve on a solar tracker I made last year. Up top is a 30 watt solar panel to charge my battery bank. Lower WAS a 15 watt panel turned 90 degrees ahead of the sun so when the sun advanced it would push enough power to a 24vdc motor to advance the tracker. I figured that can't be good for the moter having almost enough volts pushed at it all day long. So now I have gone to 2 small relays wired like a 3-way switch and a small solar panel(1.8watts, 125ma) which activates the tracker motor. So 1 relay is powered by the small panel and the other is reversed and powered by a 120v photosensor with a 9v transformer to automatically rewind upon sensing darkness. When tripped they send 12v from the battery bank to the application. What I was hoping to do now is build low voltage photosensors to advance the tracker during the day (getting rid of the small solor panel) as well as 1 for the rewinding at dark (getting rid of the 120v photosensor/transformer setup). Testing is tough this time of year with the sun being so weak and low in the sky, but is probably the best time to truly see the weaknesses (bottom line) of the tracker.
hopefully a picture. 5 lines going to the comparator. posative, negative, and output. where do the other 2 lines hook to the comparator when looking at the comparator 14 pin diagram?