Mhmm... that far, I understood... And any way to solve that the way I' m trying it? In case not, I don' t seem to have a choice..
Level shifting isn't easily possible with NPN transistors alone. Using some PNPs or a relay (or just a SPDT switch!) is your best choice
Oh, I gots an idea... I switch on the PWR button over the 5V channel, and have a relay, that switches the 12V channel on, when 5V has current... Since this NPN is a voltage follower instead of a switch... This idea' s been with me eversince those fan speed controllers... which were posted by um... acrononimous? or something alike... Maybe that' ll end my worries... eventually, lol (I' m such a burden to you guys, so bad it' s hopeless)
If you have the relay, there's no need for the transistors at all. Or are you talking about the transistors for something else?
I dunno... I think the relays would be the problemsolvers... I' ll be able to switch anything using no transistors... ^-^ Now only one thing to solve... space... what to do with the compacity of this whole... according to your programmed fancontroller (the possibly very coded one) with 3 cables, that should be no issue.. unless it' s all in the chips?
I have 9.6kbaud SPI comms between the microcontrollers, which you're not going to be able to do with ICL7107's!! You can't really compare a logic system with a microcontrolled system. From the looks of this thing you're making, it's going to be massive.
LOL, thanks... No, I didn' t want to do this microcontroller thing with a logical current-to-digit converter chip... I just wanted to compare that chips take less space than a ful circuit... If I had a microprogrammer, and understood the language, I could make a microchip... But, as a counter part in just starting electronics, I don' t have the experiences in it to get this controller rightly programmed... I' ll have to see what relay does which, and what sizes they have them... Depending on that, I' ll have either a problem with space or none at all...
no, because you are trying to relate the amount of current/voltage going thrugh a transistor with whats at it's base, and this simply isnt the case. a transistor is not a load. a transistor NEEDs a load in order for any current what so ever to flow thrugh it. once you have a load, you NEED a voltage source. a transistor will not create voltage if there is none. and you cant put a relay in series with your voltage source, it has to be parallal to it. otherwise your circut will be pulling its voltage thrugh the relay, which will meen it will not get 5v, the relay coil has resistance. to add a relay to that circut, you have it taped in like the test point, but then going to ground after the relay
The transistors have a voltage source, for that load, I have no idea what that is... EDIT: Equal to transistors, then... *sigh* this is getting illogical okay, a double relay then... So that it has a switch, operating its switch ability, and two switches inside controlling its power passage...
***.. you are overcomplcating this tromendously. this isnt hard. i had thought that my explnation made it easier, not harder. here is what you are trying so hard to do... excuse the (sp?) and MS paint TRANSISTOR VERSION: EDIT: note, R4 = 10k, R3 = 1k RELAY VERSION:
Ah, soooo... well, it possibly became so difficult for me because my logic appearance in my brain just got offline... it doesn' t really appear to work anymore... So you are explaining that the same thing I did, to the 12V, which was the issue at the very start, is the right way to do it? That just the 5V one would never work? -.- you could' ve kinda said so in the very start
editted again: http://www.howlingwolfcompany.com/temp/Fancontroller2.gif So now explain me, why did I use this 1K and 10K resistors? As far as I' ve figured, I need the 1K to put it into current, instead of voltage... and the 10K to allow the transistor base to get more than the GND, and put the current back into voltage...
the 10k is a pull down, to shut the transistor totaly off the 1k is to limit the current that it draws from +5
Ah, okay... Thanks for the advice... now are you sure this would really work? Just wondering... EDIT: Since it was such an issue that the 12V wouldn' t be 12V anymore... or is that not thanks to the transistor?
err, you will get 11.3 volts, techincaly, except no power supply is exactly 12v, most are a little over, so 11.5v will be fine in any case where 12v is needed. i am going down to my shop to proto this out. give me 10 minutes
For the transistor version, you have the transistor in an emitter follower configuration, so the emitter voltage will be 0.7v lower than the base voltage. The relay version may work, but include an inverse diode across the coil to stop voltage spikes when the switch opens.
