HC 05 With 2-3v lithium cell

[Geethesh]

@kowshik1729 I wish to use led in series because I want the all circuit so small .
To make a key finder device .
My hc05 didn't burn out it was working when I connected it to arduino 5v after that.

[kowshik1729]

@Geethesh Nice. So if you want to limit the voltage instead of using an led in series use a resistor. It's a great alternative because resistor can easily tolerate little amounts of current surges and can make the voltage drop a little bit. So try using it..!!

[Geethesh]

@kowshik1729 I just find that hc05 is not getting much ampere(current) from that battery.
That is the main problem .
Amps
What to do

[kowshik1729]

Can you share me any specifications and picture of the battery??

[Geethesh]

@kowshik1729 this link also include data sheet link

[kowshik1729]

@Geethesh I've seen your battery specifications. The battery you are using gives out 3V which is a nominal voltage but you must take one more parameter into consideration while choosing a battery for your applications. It is nothing but Amperage that it can supply.

I will explain "WHY?" ampere rating is so important in your application. HC-05 module draws most of the power from the battery while transmitting the packet data, it almost draws 200mA of current at a voltage of 3.3V this means the battery you are going to use must supply current at this amounts. But if we see the battery that you have to use i.e CR2032 which is a coin cell battery, its maximum supply current is just 3mA but our minimum required supply current is 200-250mA which is way too high for the battery to supply and that is the reason of your failure.

So, please use these battery types of Li-Ion batteries which can give a high supply current of order 500-700mA at 3.7V. I've been thinking that you are using these since the start of our conversation and that lead to my misunderstanding and made the correct reply late. Sorry for the delay. All the best...!!

[Geethesh]

@kowshik1729 thank you