I'm not sure what that means; if you are under the impression that things "output" current, you are mistaken. Current is "pulled" from a device, not "pushed" to it. That's the best layman's way I can put it. It depends on the resistance of the circuit and the supply of the voltage across that resistance - ohm's law - I=V/R - so if you have -zero- resistance (ie, a short) the current effectively becomes "infinite". If you have a break (an open), thus "infinite" resistance, then the current effectively becomes zero.Now - if you do "cut the trace" between the output of the RX2 IC and the base resistor, and you can stick you meter in between and measure the current flow; that might be helpful (once you know the voltage output) - to know if by hooking up the circuit you'll pull more current than what the Arduino (or whatever you use) can supply (in that case, you might need to include a buffer circuit or something to help supply more current).
If you can in some manner, check the voltages without the outputs of the IC connected to the base resistors; likely the rest of the circuit is "getting in the way".
My recollection of current is that it is analogous to flow (of, say, water), measured in coloumbs/second, which I know is amperes. Voltage is joules/coloumb, and specifies how much "punch" each unit of charge has.
This is a good analogy. The next sentence should logically read something like "Therefore, it's obvious that a tiny diameter pipe connected to the water source will have a very high resistance, and therefore the flow into it will be small, while alarge diameter pipe will have a low resistance to water flow".
In any case, I was under the impression that too much current through a circuit would fry something. For example, let's say the RX chip outputs 5V for pushing the car forward. Can I really just connect a wire from an output on the Arduino to the location on the board where the chip was outputting its 5V signal and everything will work? Do I need a resistor in there? If I understand you, the answer is no, and the circuit itself will dictate the current.
Quote from: cr0sh on Oct 21, 2012, 07:06 amIf you can in some manner, check the voltages without the outputs of the IC connected to the base resistors; likely the rest of the circuit is "getting in the way".Any idea how I can do this?
I also drew a rough sketch of how I believe the circuit is designed for the motor controller. F_ic and B_ic are forward and back on the IC, respectively, and M_f and M_b are motor forwards and backwards, respectively. I'm sure I violated all sorts of standards for circuit diagrams, so forgive me, but I think the general idea is there.