How much Current does a SNES cartridge receive?
As much as it asks for, up to the amount the voltage regulator can provide? If I remember what other people have said, something like 5V@700mA are available to the cartridge? If you exceed that, you'll get varied badness.
What are you really trying to do?
I'm not experienced with transistors, I'm getting into them so I can use one as a single NOT inverter, because I am incorporating a chip on the cartridge, a CMOS chip that uses an Active High Reset signal. Since SNES is active low RESET, I want to invert the Reset signal to the Reset pin of my new chip.
I'm very inexperienced with all the different types of Currents, and the addition of transistors. I can understand the flow now after learning about them, I just don't understand the relationship between current at the BASE and current at the Collector, depending on when the BASE is on/off. Or what resistors I should best choose, keeping note I am using a CMOS chip. Here is a general picture of the schematic for my NOT inverter.
Note: The input signal is only connected to the BASE, not the emitter (as it can be mistakenly interpreted). The emitter is only connected to GND, tested it myself, this circuit with an LED. All I can really say is that the LED gets less juice than the other LEDs, because I use a considerably lower resistance to VCC for this LED, and it outputs just about the same light as the other 'normal' in-circuit LEDS with higher resistances to VCC. I know that also matters that those other LEDs currents are coming from IC pins, so it matters what current those pins are sending out.
I'm just trying to figure out how current works in the circuit, in general, and in specific to this transistor so I can know how to treat it with regard to the CMOS IC I will be incorporating. However, it would be nice to know in general if current matters at all to a logic pin whose logic level relies on voltage.
Alright I'm out
lidnariq wrote:
As much as it asks for, up to the amount the voltage regulator can provide? If I remember what other people have said, something like 5V@700mA are available to the cartridge? If you exceed that, you'll get varied badness.
What are you really trying to do?
I added some response to you in my post above this one. I have more to say:
You say "as much as it asks for." I also thought this way, that a component would only suck up as much current as necessary. However, then why do transistor circuits as I am learning call for a resistor before the Base pin?? Why doesn't that base pin only use as much as it needs? They say without the resistor you frisk frying the component. I don't understand, since all the IC components I learned about I learned as only using what they need, no risk of fry. Why is this transistor different? What other components are like this? Can you explain it?
I learned about the general flow of Transistors, without regard to specifics on current levels, here:
http://www.cs.bu.edu/~best/courses/modu ... ors2Gates/It's a great beginning tutorial IMHO.
I found good info here: I just haven't made sense of it all yet,
http://electronicsclub.info/transistorcircuits.htmA key part I believe in understand is this section:
Code:
The base-emitter junction behaves like a diode.
A base current IB flows only when the voltage VBE across the base-emitter junction is 0.7V or more.
The small base current IB controls the large collector current Ic.
Ic = hFE × IB (unless the transistor is full on and saturated)
hFE is the current gain (strictly the DC current gain), a typical value for hFE is 100 (it has no units because it is a ratio)
The collector-emitter resistance RCE is controlled by the base current IB:
IB = 0 RCE = infinity transistor off
IB small, RCE reduced transistor partly on
IB increased, RCE = 0 transistor full on ('saturated')
Not eveything uses just what it needs; sometimes you must limit the current to something (e.g. an LED or the base of a transistor).
bazz wrote:
You say "as much as it asks for." I also thought this way, that a component would only suck up as much current as necessary.
"As much as it asks for" is not "as much as it needs".
A diode, or the base-emitter junction of the BJT, will sink as much current as necessary to cause the voltage across it to be approximately 1V.
It looks like you've found other sources for the other questions you ask.