Top half of the circuit is fine now. Despite the small amount of magical smoke in those IC's, it absolutely stinks, and lingers around for ages! I couldn't find the diagram you're talking about in the datasheet - what figure number is it? or was it from another website? Was the idea that you'd have a separate IC per item that you're trying to measure? And that if you wanted to turn off that item, you'd remove power to the IC too? Have fun
Yeah, the power of the IC's are to be turned either on or off... and maybe if it' s possible, to use as low of IC' s as possible, so for Freq-Volts transfers, you would need one, why not measure Freq separately, then... or for Thermistor resistance measurements, you' ll need a separate one too, so then you just split them all up... One broke, one fix... easier... (I' m the one who' s not into break = buy new things) The sheet I have is here: http://www.howlingwolfcompany.com/temp/schematic.gif and yes, I know of the GND between it, but that' s something I can' t work with properly... since I have none... future to be changed, anyway, then I will... EDIT: In the new one, would it help more, if I cut the positive power, in stead of the negative? Since it flows from positive towards negative, that sounds more logical to me... However, the transistors would still decrease some power... I have no idea solving that problem... it' ll come... some day
I don't see how you don't have 0V if you are using a split rail supply capable of -12V, -5V, 5V and 12V. Ground doesn't mean earth in this instance, it just means the centre tap of the transformer, or the 0V reference. Surely there must be 0V present in your power supply? It would be possible to connect several displays through latches to a single ICL7107 if you wanted to keep the costs down. (at the expense of time between samples).
The GND is the 0V, the middle cable of 3/5 in my case... Not 0V of 12, and not 0V of 5, just 0V in total... the 5V will be made out of the 12V... so the 0V is relative to both... Serveral displays is what I need, not a single one... every fan has a controller... And then there' s a main power supply for the fan controllers (this includes the fans), if you followed this thread, you could see that in my old posts... I' m not really worried about the costs, this is most likely to be a theoretical learning project whatsoever... I don' t know all prices, so I' m not panicly yet, lol... But it' ll be expensive alltogether... I' m really sure of that...
Indeed... I' m learning to calculate things now, because I' m almost trough with this part of the design... then I' ll be adding values, and then you can comment more, lol... The redesign will be together with the values... all at once... easier...
Wow! Learning electronic calculations really r0x0rz... I mean... it' s so cool, and it makes more sense to me than my former mathmatics... With all those I, P, R and U' s and their maths... just don' t use difficult formulas, lol... I' m trying various ways of calculating current, voltage, resistance and more... But... now I' m stuck with one thing... what is the most common I of a NPN transistor...? May sound weird, but it drains 0.6V in many cases, right? So then it must have some I, too... (for those who bother, I = Amps) Anyone got a reading or maybe a link... I' ll be searching in online shops' catalogs...
a standed bipolor TO-92 transistor can handle ~400ma, or .4A upgrade to TO220 and your in the 2-5A range (higher with apropreate heatsink) of course, a TO-3 can handle much more, up to 30A
Wow, they eat a lot of amps... compared to those tiny amp-eating LED' s... they use just 20mA/0.02A... And I' ve learned so much more that I made a lot of notes... what' s the most common reading of NPN's? ~400mA?
No no no no, theshadow wasn't stating how much current transistors take, but how much some of them can handle. You draw some current through the base to turn the transistor on, but it depends on the gain of the transistor and the load connected to the transistor.
Oh, okay... ^-^ new things all over... this actually is quite addictive... no wonder you guys know so much, lol... I love electricity... but anyway, so you draw only power out of a base-side of the transistor, well amps... the transistor only keeps 0.6V (in most cases) for itself, and the rest passes trough... However, how do you amplify, is that by increasing either I, U or P...? EDIT: I = Amps U = Volts P = Watts R = Resistance
A small current at the base-emitter junction allows a large current to flow between the collector-emitter junction. The 0.6V is required to cause the junction to start conducting, but in reality, it's usually about 0.8 or 0.9V before the junction is fully saturated. You'll have to read up about transistors - there's a lot to learn.
I' ve noticed... I' ve been on transistors for a month and there' s still so much to know, it seems... EDIT: Here' s my idea on transistors, so far... as far I can illustrate it..
Well, as switches, it's sort of like that. You'd have the load at the bottom on the PNP transistor diagram. At the moment, it's an inverse voltage follower. The NPN can be approximated like that for switching purposes though. After four years on an electronics degree you only just learn everything about transistors & their uses.
Compared to you, I' ve had only say 2.08% of time to learn these things, so far... lol So that' s something really nice... this far on a month...
You'll learn a lot quicker how they work and what not to do once you destroy a few Get a breadboard/prototyping board and some components and start fiddling. Best way to learn after you learn a bit of theory.
If only my money had arrived... I' m waiting for 325 EUR that' s been delayed till end this month... bleh
Started on version 2, with values this time... http://www.howlingwolfcompany.com/temp/Fancontroller2.gif Maybe for the first time, no errors in this part yet... ^-^ math solves everything... or so...
Not quite right: Resistors for LED = (Supply Voltage - LED Forward Voltage)/Forward Current (5 - 2.2)/0.015 = 187R So you'd want a 200R resistor for the LEDs. Base resistors: This is going to depend a lot upon which kind of transistor you use, but 8.2R is definitely far too low. For most purposes, you can use a resistor in the region of 470R to 1k. I assume you're trying to turn on or off whatever is going to be connected on the right hand side of the picture and the connections on the left are the supply. GND is the same thing as 0V. You don't need another connection, they should be connected together. Q2 is fine, Q3 won't give you 12V. Q1 is ok.
