Electronics > Beginners
Some noob questions
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PA4TIM:

--- Quote from: Mr D on July 16, 2018, 09:28:20 pm ---

I don't understand this. The more power-hungry the lamp, the less amps it needs? Seems like the wrong way round?!


--- End quote ---

10 ohm draws more current as 20 ohm when the voltage is the same. 20 ohm is less powerhungry as 10 ohm. 1 ohm is even more power hungy.
10V / 10 ohm = 1A , this is 10V x 1A = 10W
10V / 20 ohm = 0,5A, this is 10V x 0,5A = 5W, so less power

It will become even more fun if you get to AC and paracitics  >:D
Mr D:
My brain hurts.

Just one more before i go to bed:

I don't get it. You're talking about a load drawing the current. The greater the load, the more current.

But at the same time the circuit has resistance.

So it's pulling and pushing back at the same time??
rstofer:
In the usual workings of electronics, current is a result, not a cause.  Yes, there are current sources but they are rare unless working with op amps built from discrete components.  I can't recall ever playing with them but I do know they exist.

Usually, I have a voltage source (battery or power supply) and I have a load (as simple as a resistor or as complex as a PC) and the result of operating the load on the source results in a certain current flow.  The current is the result, not the cause.

It doesn't matter much because Ohm's Law relates all 3 variables and we can swap them back and forth at will.  When you get to Kirchhoff's Laws, you will be writing equations in terms of current flow or voltage drop.  This is where it will all make sense.  In fact, it isn't even possible to analyze a simple op amp circuit without writing Kirchhoff's Current Law at the inputs (explicitly or just winging it).  It's simple to write (in the case of linear feedback, less so if the device is used as an integrator) but key to understanding how the closed loop gain is calculated.

Get the idea that water pressure is kind of like voltage, pipe friction resistance is kind of like electrical resistance and water flow rate is like current and then put the analogy away.  It was just created to give an intuitive feeling toward the 3 fundamental units.
bsudbrink:
Nothing "pulls".  Everything "pushes".  Except maybe inductors but don't try to understand those yet.
PA4TIM:
A lower resistance is a higher load.
In Dutch to make it more clear for the TS: "Iets belast een voeding meer, de belasting is hoger omdat de weerstand lager is. Er kan dus meer stroom lopen, dat maakt de boel warmer en vormt zo een zwaardere beslasting.

https://www.youtube.com/channel/UCOausWDNRDJikQ11gSLj7nA , this man is a Very good teacher
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