Ive been doing a lot of reading lately trying to understand the basics of electronic circuits. I can build a circuit from a schematic, but I want to understand why a capacitor goes here and a resistor goes there.
But even with all this reading I still find myself confused about what could be the most basic principle of electronic circuits, ohms law.
My confusion comes down to this, is current being pushed or is it pulled through a circuit?
And here is what is causing my apparent lack of understanding, a simple AC to DC wall adaptor. Let me try to explain.
I can buy two wall adaptors. The first one converts to 12V 3.7A, and the second one converts to 12V 1.5A. Now if I plug each of those into their own circuit with a 300 ohm resistor, ohms law says that the current flowing in each circuit is 40mA and the power dissipated by the resistor is 480mW. Now if that is true, then to me 40mA of current is being pulled through the circuit, and the rest is just sitting around waiting to be used. As long as I dont pull more current than there is available Im fine.
Or, Im totally wrong here and Im going to start blowing up poor helpless resistors? Because the amps from the wall adaptors are 3.7A and 1.5A respectively. And if I use that current rating in the ohms law calculations, then my circuits power dissipation is going to be a great deal more than a little 1 watt resistor can handle.
Hopefully that explains my confusion.
But even with all this reading I still find myself confused about what could be the most basic principle of electronic circuits, ohms law.
My confusion comes down to this, is current being pushed or is it pulled through a circuit?
And here is what is causing my apparent lack of understanding, a simple AC to DC wall adaptor. Let me try to explain.
I can buy two wall adaptors. The first one converts to 12V 3.7A, and the second one converts to 12V 1.5A. Now if I plug each of those into their own circuit with a 300 ohm resistor, ohms law says that the current flowing in each circuit is 40mA and the power dissipated by the resistor is 480mW. Now if that is true, then to me 40mA of current is being pulled through the circuit, and the rest is just sitting around waiting to be used. As long as I dont pull more current than there is available Im fine.
Or, Im totally wrong here and Im going to start blowing up poor helpless resistors? Because the amps from the wall adaptors are 3.7A and 1.5A respectively. And if I use that current rating in the ohms law calculations, then my circuits power dissipation is going to be a great deal more than a little 1 watt resistor can handle.
Hopefully that explains my confusion.