| Electronics > Beginners |
| Some noob questions |
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| rstofer:
Dave has a playlist of Fundamentals videos. w2aew has some great videos on circuits. Both of these sources are somewhat beyond Ohms Law but they are both excellent resources. Digilent has an entire curriculum: https://learn.digilentinc.com/classroom/realanalog/ MIT has OpenCourseware https://www.google.com/search?q=mit+opencourseware+electronics+video+lectures Khan Academy has an Electrical Engineering track but they are best known for their math lectures: https://www.khanacademy.org/welcome?learn=1 I can't begin to list all the excellent resources, there are tutorials all over the Internet. |
| Mr D:
--- Quote from: PA4TIM on July 16, 2018, 09:52:32 pm --- 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. --- End quote --- Haha, thanks, i can read it but i'm actually English! ;) Thanks all, now to bed. Sorry for coming across as a dumb-ass, i have zero background in this stuff. I can't promise not to resurrect this one tomorrow! |
| rstofer:
--- Quote from: Mr D on July 16, 2018, 09:47:04 pm ---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?? --- End quote --- Load isn't a fundamental unit of electricity. Volts, amps and resistance are fundamental units. Intuitively, we think of a heavy load as drawing more current than a light load and for equal voltages, we get to the idea that a heavy load draws more current and therefore must have less resistance because, for a fixed voltage, current and resistance have an inverse relationship. E = I / R Hold E constant and to increase current, you need to decrease resistance. Increase resistance and current must decrease. We could also consider load in terms of power and this would allow for different voltages as well as different resistances and therefore different current. We don't need to go there. Ohm's Law does it all! https://www.electronics-tutorials.ws/dccircuits/dcp_2.html |
| rstofer:
--- Quote from: Mr D on July 16, 2018, 10:04:46 pm ---Haha, thanks, i can read it but i'm actually English! ;) Thanks all, now to bed. Sorry for coming across as a dumb-ass, i have zero background in this stuff. I can't promise not to resurrect this one tomorrow! --- End quote --- Going to bed at midnight? That's prime time for doing homework as I recall! Don't worry about resurrecting the topic. It is the most fundamental discussion you will ever have on the topic and it needs to be nailed down or you simply can't move forward. |
| Jwillis:
The water analogy is correct if explained correctly . Think of a tank of water with a pipe attached to the bottom. The amount of water in the tank is the "charge". The pressure of the water is called "volts " .The more pressure the higher the voltage. The flow or rate that the water moves is called "Amps" or Current. The size of the pipe is called resistance. The bigger the pipe the less resistance. Now voltage and current are dependent on each other. No pressure on the pipe no flow or current. Put a plug in the pipe Even with increased pressure there is no flow. Now lets consider your circuit is a paddle wheel at the output of the pipe.The paddle wheel can only handle so much flow before the water pours over the sides. This is the flow rating or current rating .no mater how much water is dumped into the paddle wheel it will only except so much.Lets say 1 amp . So your paddle wheel requires a certain amount of pressure and flow for it to move but also has a maximum pressure and flow before it breaks. You set your pressure an flow at a required amount to make the paddle wheel move. Just like 3 volts and 1 amp.Every thing works fine. Now lets say the flow remains the same but you increase the pressure .12 volts at 1 amp and like dirt in front of a pressure washer your paddle wheel promptly explodes and flies apart . Just like a circuit only excepts a certain amount of flow or amps .If you increase the pressure or voltage beyond its rated requirements it will burn out .A circuit .when working correctly ,will only take so many amps no matter what the voltage is. This is also why voltage is the dangerous part of electricity. Very high voltage with very small amps will kill where as very high current and very small volts will do little. Now lets consider the size of pipe .Just like wire ,the bigger the pipe or wire the less resistance there is. Hope this helps |
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