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I have some doubts and confusion. Please clarify by explaining the science behind it. Thank you. I have no knowledge in electicity. Regardless what i put as voltage and current is just example, just want understanding on it.

Hypothetically, a charger output 5V 2A, device input 5V 0.5A will it work? I read that if input is lower than output will work because device draws what it demand from charger and current is low so preventing cable and charger heating up which may lead to fire.

  • Everything should be fine because communication exists between charger and device due to the circuitry component thing of device and charger (please clarify). Device has a charging controller component in it and so do charger. Device can be phone, tablet, laptop, electric fly swatter, etc. whereas charger can be power bank and power brick or corded wall wart.

  • However, someone pointed despite working fine its damaging charger due to heat building up at charger and will die at point (please clarify) and

  • some say by charger will supply its stated current in this case 2A than the needed 0.5A it will cause battery to swollen (please clarify). Does this has to do with the circuitry thing?

On the other hand, if a charger has output 5V 2A, device input 5V 3A will it work? I read that if input is higher than output will not work because device draws what it demand from charger and current is high so it causes the charger to heat up and oversupply which may lead to fire in cable and charger and blown fuse in charger.

  • Everything should be fine because communication exists between charger and device due to the circuitry component thing of device and charger (please clarify) mentioned above because

  • I read charger will only supply up until its stated current output so no blown fuse and device just chargers slower? (please clarify)

  • What if the voltage and current output is different from required v and I input? Will it work? I read it should because regardless voltage higher or lower it wouldn't work cuz too high device swollen and heat up while too low device wont charger or work. (please clarify)

  • How about current how does current gets affected in this situation when voltage and current is different? I just know (no knowledge about it, just informed about the words) is depending on device and charger intelligence and the communication circuitry thing,are there more? Please clarify help understand things. Thank you.

I hope you understand what I'm talking about.

Transistor
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Alienxalienz
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1 Answers1

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There is a fundamental problem with the word 'charger', which is designed to charge a battery. It is different from a 'power supply', which is designed to power a device. The two things can and generally do behave differently. They are designed to behave differently. However, people often use the two terms interchangeably, so confusing them.

Sometimes a charger is built into a device, and requires an external power supply.

Sometimes the power supply and charger are built into the same unit.

A charger should only be used with the battery it has been designed to charge.

If the power supply and device are 'dumb', then the supply should have the correct voltage rating for the device. The device may specify a small range, like 5 V +/- 0.5 V, or a big range, like 8 V to 32 V, or it may only give a single voltage figure, in which case you are probably OK with +/- 10%. The supply should provide at least the required current, the device will only use the current it requires.

Sometimes a device may be built to accept a range of voltages and possibly draw a range of currents, sometimes by communicating with a 'smart' power supply. If the power supply, device, or both are 'smart', then you have to read the manuals to see what they have been programmed to do in various circumstances.

Neil_UK
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