Small introduction to Voltage Sources and loads

Voltage Sources are divided into

• DC source - Direct Current
• AC source - Alternating Current

As the name specifies in DC, current flow is only in one direction, but in AC it changes its direction of current flow for a particular interval of time. In electronic we don't use AC much so we can discuss DC source in detail.

AC is mainly used for transmission of  electricity,

In Indian house, we get a standard supply of  230v,50hz, sinusoidal. this an AC supply we cannot use it Electronic devices because Electronic devices use DC, AC can be converted into DC by a device called Rectifier. similarly, DC can be converted into AC by a device called invertor or an Oscillator.

DC power sources are mainly batteries and wall adapters(which convert AC into a required level of DC)

the battery has a specification of 2200mAh, 3.8v, 8.3Wh

The battery is lithium-ion battery, it delivers a maximum output of  3.8volts, and delivers a current of 2.2Amps(2200mh)

The term mAh(milli Amp hours) tells use how long does our battery work, 

Voltage delivered by the source depends on the battery output voltage but 

the current delivered by the source depends on the load resistance, 

This can be clearly explained by ohm's law 

V=IR

Voltage across a component in the circuit is equal to the product of current(I) and resistance of the component (R),

the above equation can be written as 

I=V/R

I∝1/R

This proves that when the resistance of the circuit increases the current through the circuit decreases

and the vice versa happens when the reverse takes place.

when this battery is kept in a circuit draws 2.2Amps(2200 milliamps) from the battery,

 the battery drains completely in 1 hour,

this is  mentioned as mAh,

so the life of the battery depends not only on the capacity of the battery but also the resistance of the circuit on which the battery is used,

from this, it's clear that the current specification any power source is only the maximum current which it can produce,

In the battery, it is also mentioned that 8.3Wh, which is nothing but the maximum power which can be delivered by the battery, in this case, it is (3.8volts*2.2Amps=8.3 watts)