Like I understand wattage and that a light bulb uses way less watts than say an electric dryer. But what causes less current to be supplied to the light bulb vs the dryer? I assume the power being supplied by the grid wants to force electricity out at a constant rate. So what is built into various circuits that causes the appliance to accept current at a higher or lower load? Is it simply just resistance? I can’t seem to wrap my head around this one.
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>Is it simply just resistance?
Yes. Voltage is set, the only thing that can vary is intensity, and you can make that change by modifying resistance.
You only need 2 formulas: V=R.I (ohm’s law) and P = V.I (watts). You can asssemble them and have P = V² / R , or P = I²R .
Your typical resistor in an electronic circuit is rated for 0.25W heat dissipation, because it is not supposed to heat, only to filter signals. There are bigger resistors that can take some heat typically used in CRT screens or race cars shutoff systems. They usually dissipate up to 10W.
But there are other kind of resistors, specifically made to dissipate a ton of heat. The one in your oven that goes bright red usually has a 25ohm resistor value, meaning applying 230V to it creates a circuit that needs to dissipate about 200W. Your head dryer does something similar.
electronic cigarettes resistors use the same property, except they work with 5V or less, so they need to have lower values. I made some that went under 1ohm when I was vaping. The material is specific, it used to be kanthal but there are other alloys.
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