Need advice on a music device which can run 20 hours on a charge

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AMG

AMG

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Expandable memory welcome, but not absolute necessity.

Cheaper the better
 
hotshot05 said:
Get a power bank and a music player which can be charged via USB. And your job is done.
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I'm thinking of giving up on carrying a smartphone and reverting back to my 2220 slide. Tech de-addiction, you see.

And for the media device I was thinking of something like an ipod etc but one which can last for 20 hours.
 
Your 2200 Slide has a memory card slot right?
Put all the music there.

And get a power bank and a USB to Nokia small pin cable. The nokia chargers output at 5V only. Your only concern will be whether the power bank can determine that the phone needs very little current(the nokia charger output is rated at 5V, 350mA). Today's smartphones can tell this to the device providing them power. Not sure if older Nokia phones can do this.
 
Criminal said:
^^ current doesn't matter. any 5V charger supplying more than 350mA would work.
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If the power bank does not understand what phone is attached and how much current is required, it can supply any amount of current.
If overcurrent protection isn't there, the regulators inside can blow easily. A phone which takes in normally 350mA current, if supplied with 2A current, things may not be so pretty.

A 7805 regulator IC can stand an input current of 1A. A friend attached his laptop adapter(19V, 3A) to the 7805. It blew out instantly. The thermal limit was exceeded since the input power was more than what it could withstand.
 
^^ i am 100% sure that the voltage spoiled your 7805.

if a circuit needs 350mA then it'll draw only that much current from a 2A power source. it won't go kaput unless you force-feed it high voltage.
 
A 7805 can withstand 35V input voltage. Says so in the datasheet. The datasheet also mentions the max power input. Actually the power input exceeded this threshhold. 7805 is a linear regulator i.e part of the power input is dissipated as heat. Without a heatsink, it can dissipate only a specified amount of heat.

Normal chargers are not constant current sources. They are constant voltage sources. Just hope the circuit inside does not go bonkers and supply more current than necessary.
 
^^ i also referred to its datasheet before replying but i read it wrong... it was meant for output voltage (5 to 18 V).

now, i am clueless about your issue as i use 7805 every now and then with a 2A mobile charger. i have another circuit using 7805, running 24x7 for the last 5 months on a 12VDC 3A LED driver. 7805 supplies current based on the load, which in my case was always within the limits.
 
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