# connecting pam8403 and bluethooth module in series

I am new to this so I apologize in advance for any rookie mistakes.

I decided to make a portable Bluetooth speaker.

I have a pam8403 and a Bluetooth module:

Both of them require 5 V input.

Can I connect both of them in series and connect a 12 V battery to power them?

Is this possible?

• No, 5+ 5 ≠ 12 and what if the grounds are the same on the signal interface? then it becomes a short circuit. – Tony Stewart Sunnyskyguy EE75 Jan 19 '19 at 16:25

No. You cannot connect the two items in series.

First of all, 5V+5V is less than 12V - you are still two volts short.

Second, the voltage will not divide evenly across the two. Consider them as a voltage divider:

simulate this circuit – Schematic created using CircuitLab

If the two devices needed exactly the same current to operate, then they would have the same resistance and would divide the voltage equally.

It is very certain, though, that they do not need exactly the same current to operate. The voltage across each one will be different. Since they are active devices, the current each consumes will change continuously - the voltage across each will therefore also change continuously.

Even it it did divide evenly, you still have the problem that you must connect the ground of both devices together. That puts a short circuit in to your voltage divider.

So what do you do?

Use a regulator to reduce the 12V down to 5V.

There are switching modules that are easy to use, and linear regulators that are cheaper though more wasteful of energy.

can i connect both of them in series and connect a 12v batter to power them is this possible?

No, it is not possible... you cannot do that.

Please go with some buck converter or a linear regulator.

• yes, i added a 7805 ic , it was working fine but, some squeeze sound was comming out of the speaker , how can i solve that. – Akhil Jacob Jan 19 '19 at 17:24
• The devices will not work like what you are thinking. The devices what you are planning connect in series are semiconductor devices.so many factors needs to be considered. They will not work like two simple resistive loads connected in series (some basic voltage divider kind of thing what you are thinking) – Satish Singupuram Jan 19 '19 at 17:29
• so what should i do – Akhil Jacob Jan 19 '19 at 17:31
• Please go with some simple 1. voltage regulator or 2. Buck converter... it's already mentioned in my answer. – Satish Singupuram Jan 19 '19 at 17:33