electronics doubt amplifiers and nokia battery.please help!!!!!?

[HARISH]

hello guys i want to know

1)what is the use of impedance and admittance.i mean the purpose why is it necessary?

2)in nokia battery do they use capacitors to store electricity or do they use our normal chemical made batteries

[Shakhawat H]

1. they are electrical parameter in ac current. Impedance, z = V/I

2. Nokia use chemical battery, Lithium ion battery

[billrussell42]

2. They are chemical batteries. Capacitors would be more than 10 times larger, perhaps 100 times.

1. They are parameters that enable us to make calculations in AC circuits. They are not necessary unless you want to make those calculations.

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