Why electric devices do not draw more current than they need?

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Discussion Overview

The discussion revolves around why electric devices do not draw more current than they require, using examples like a TV set. Participants explore concepts related to electrical current, resistance, and power supply, touching on theoretical and practical aspects of electrical circuits.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant suggests that a TV set supplied with 10 amperes can only draw 2 amperes due to its resistance, implying that the remaining current would be converted to heat.
  • Another participant counters that the concept of supplying 10 amps is a misunderstanding, emphasizing that devices draw only the current they need based on the voltage supplied.
  • A different viewpoint states that power not used by devices is never generated or sent to the grid, indicating that the current drawn is contingent on device requirements.
  • One participant clarifies that amps represent the flow of charge (electrons) and do not get converted to heat, challenging the initial claim about excess current being wasted as heat.
  • Another participant uses an analogy of a nuclear power plant to illustrate that a single device, like a TV, will not consume all available current when connected.
  • A further analogy involving a water tank is presented to explain how current flow is regulated by resistance, suggesting that devices only draw the amount of current that can pass through given resistance and voltage.

Areas of Agreement / Disagreement

Participants express disagreement on the initial premise regarding current supply and draw. Multiple competing views remain regarding the nature of current flow and the implications of resistance in electrical devices.

Contextual Notes

There are unresolved assumptions about the definitions of current, voltage, and resistance, as well as the implications of power generation and consumption in electrical systems.

semistudent
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Tv set is an example You are supplied with 10 amperes Your tv needs 2 ampere Why can not your tv draw current more than 2 amper? If you say because ohm law , this law say that resistance resist current flow This mean the resistor of your tv set will permit flow of only 2 ampers The remaining which is 8 amperes will be prevented by resistor and converted to heat So all the 10 should be consumed by the tv set The tv is an example My question is more general Why the devices does not draw all the available current?
 
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semistudent said:
Tv set is an example You are supplied with 10 amperes Your tv needs 2 ampere Why can not your tv draw current more than 2 amper? If you say because ohm law , this law say that resistance resist current flow This mean the resistor of your tv set will permit flow of only 2 ampers The remaining which is 8 amperes will be prevented by resistor and converted to heat So all the 10 should be consumed by the tv set The tv is an example My question is more general Why the devices does not draw all the available current?
You misunderstand completely. You are NOT "supplying" 10 amps, you are supplying some voltage. The TV (or anything hooked up to an electrical power source) draws exactly as much current as it needs and there is no waste anywhere.
 
semistudent said:
The remaining which is 8 amperes will be prevented by resistor and converted to heat
Amps are a unit of charge flow. Physically, it is a bunch of electrons. Electrons don't get converted to heat.
 
Apply a little critical thinking here. if a megawatt nuclear power plant can supply thousands and thousands of amperes at 120V, do you think that a single TV, when connected, will consume it all?
 
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A water tank contains of gallons of water (charge). The height at which it's placed is the pressure (voltage). The diameter of the outlet pipe(conductance) controls the flow rate (current). Now your resistance being the reciprocal of conductance, analyse how the flow rate (current) varies as you vary the diameter (resistance) as in a tap. You won't get all the water flowing in it at once, only the amount of water that can pass through the given diameter and at given pressure constitutes the flow.
So holds I=V/R.
 

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