undefined | Better HN

0 pointsmalfist2y ago0 comments

No, it can't.

Voltage is pushed, current is not.

A device drawing 5v@5mA from a 5v 1000A supply will continue to draw 5mA if you increase the supply to 100V or 100,000A.

Or at least it will until it's fried from the extra wattage. 5V@5mA is 0.025W, but at 100V, that same 5mA pull is half a watt.

But it's always 5mA

0 comments

I am talking about a passive load (like a resistor). Increasing the voltage will push more current through it.

malfistOP2y ago

No, the resistor will pull more current.

If you supply a 100 ohm resistor with a 12V100Amp power source, the circuit is going to pull 0.12 amps from the supply.

If you supply a 100 ohm resistor with a 24V100Amp power source, the circuit is going to pull 0.24 amps from the supply.

The supply isn't pushing current, the characteristics of the circuit has changed and it's pulling more current.

It's just semantics at this point. You say pull I say push. A 24V supply can push twice as much current (through a resistor) as the 12V supply.

j / k navigate · click thread line to collapse