help to design;two DC power source as one

Thread Starter

apurvmj

Joined Sep 28, 2012
16
Hi there all,
I'm a newbie in circuits, I have unique requirement to have 12v, 100w DC power supply with 3v & 9v batteries, but without having them in series. I tried transistors but couldn't figured it out.
Will some one pls help me.
Thanks in advance.
 

Thread Starter

apurvmj

Joined Sep 28, 2012
16
those box like rechargable batteries
& about non series connection just to understand 'Op amp' as experiment.
could someone reduce Op amp for this purpose. i guess there are aprrox. 20 transistors in op amp.
 

wayneh

Joined Sep 9, 2010
17,496
You may be confused about what an op-amp does. It is NOT a way to create power. It is used to CONTROL the power supplied by a source such as a battery or power supply. A small amount of power is lost in the internal operation of the op-amp and by its associated circuit components. With good design, these losses are very small.

But the fact remains that ALL the power comes directly from the power supply and the op-amp does not increase that, only reduce it.

Does that help clarify? If not, we are having trouble understanding what you want to do with your op-amp.
 

Thread Starter

apurvmj

Joined Sep 28, 2012
16
You may be confused about what an op-amp does. It is NOT a way to create power. It is used to CONTROL the power supplied by a source such as a battery or power supply. A small amount of power is lost in the internal operation of the op-amp and by its associated circuit components. With good design, these losses are very small.

But the fact remains that ALL the power comes directly from the power supply and the op-amp does not increase that, only reduce it.

Does that help clarify? If not, we are having trouble understanding what you want to do with your op-amp.
I know that Op-amp doesn't increase the power, what I want is V1+V2. I was thinking sort of component of Op-amp, as Op-amp has few multi-transistors component in side it.

# Dodgydave
thanks for concern but these batteries are heavy duty & with series they are just good to supply 100w for half an hour or so.
 
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Kermit2

Joined Feb 5, 2010
4,162
Could you tell us the name brand of these powerful 9 volt batteries?

11 amps output for 30 minutes (=100 watt for 1/2 hour) is one HELLOFA of 9 volt battery. is it the same size as the standard 9 volt like you put in a smoke detector?

100 watts, ... :)
 

wayneh

Joined Sep 9, 2010
17,496
I still have no idea what you want to accomplish with the op-amp. How does it relate to getting V1+V2 at 100W?

Batteries are a source of EMF, electromotive force. In a circuit, you can't get more electromotive force without adding more sources of EMF in series. There are ways to boost voltage. Perhaps you are looking for a boost circuit?
 

Thread Starter

apurvmj

Joined Sep 28, 2012
16
By saying op-amp I doesn't mean it literary. I don't intent to use Op-amp as whole, may be diffrent design of power transistors, inspired from Op-amp. I heard that OP-amp used as summing amplifier. I need any circuit to get 3v+9v=12v, as a power source but you may ignore 100w requirement.
Hope I make myself clear this time.
 

Kermit2

Joined Feb 5, 2010
4,162
Any circuit you make will have to 'ADD' the voltages.

In other words, the circuit will put the battery voltages 'IN SERIES'.

The other option is to use a wide range input Boost converter that will produce 12 volts with either 3 volts input or 9 volts input. With this method you only use one battery at a time and not both.


You decide.
 

RamaD

Joined Dec 4, 2009
328
Still not clear as to what your requirement is.
The output of the opamp comes from the power supplied to the opamp through its power pins. The current capacity of the output is limited to the opamp's output capacity and not that of what is connected to the inputs (batteries as you intend).
 

Thread Starter

apurvmj

Joined Sep 28, 2012
16
thanks for that.
kindly refer http://www.allaboutcircuits.com/vol_3/chpt_4/7.html in this "Common-base circuit for DC SPICE analysis" graph you can see 'series-aiding effect'. but base-collector loop gets saturated at 1.2v & I want to operate at more than that. So I need something like this?
What I've observed that when I say something like Op-amp, people stick to Op-amp only. I only mean I want any circuit, simple & made for the purpose, may be inspired from say Op-amp.
Thanks.
 
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