Iām a software guy, but I have been doing basic hardware stuff for years. I want to say that I am enjoying this āprep-preā stuff. Yeah, I know this stuff, but Gus is explaining it really well.
I had never heard, āwhat a resistor does is convert voltage to heatā. Somehow that was clearer than any explanations about resisting current flow. If a resistor is converting voltage to heat, then obviously the voltage on one side will be different than the voltage on the other side - because some of that voltage was converted to heat.
Why do we need a resistor? Because the LED only wants one volt and only so much current. So, I need to lose 2.3 volts before I feed the LED. Somehow, I have gotten by with simple circuit design for a long time without ever understanding it quite that way. Thanks.
@ Blue Hair Bob - a small correction, it is better to say it converts the electrical energy (not voltage) to heat.
In the early days, it was very hard for me to understand the difference between current and voltage! But thinking of a voltage add a bag of charge and the current as the how many bags are getting across was what made sense for me.
Another one is why an unconnected pin is not zero volts, and why it is āfloatingā. This is for another tech talk
Ah, ok. I did not know that individual electrons each had a charge of 3.3 volts. I thought they had a negative charge, actually, and that positrons had positive charge. Or that you needed two things to measure voltage. But my physics teacher was a bit loopy. He probably made all that stuff up.
(dad was a physics prof, so I am pedantic about this stuff, because ⦠science) So, technically, an electron does not have a charge of 3.3V. It has a charge of 1.602e-19 coulombs, or energy of 1.602e-19 joules when moved through a potential of 1V. The numbers are actually not interesting - the bit that matters is that voltage is a difference in potential (electrical āpressureā) and current is a flow of electric charge. And yes, this is way more than one needs to know to light LEDs, but I didnāt want to leave the misconception that an electron has a voltage of 3.3V.
Like water in a pipe pressure that is exerted upon the water filled pipe at one end, appears at the other end of the pipe far far far faster then the actual water moves through the pipe. Electrons drift along slowly in a conductor. The drift velocity is on the order of millimeters per hour, but increases with voltage.