# voltage and current

Discussion in 'General Electronics Chat' started by harikanaidu, Nov 28, 2014.

1. ### harikanaidu Thread Starter Member

Nov 28, 2014
76
1
how can i get the same voltage at the output as in input with increasing current

2. ### harikanaidu Thread Starter Member

Nov 28, 2014
76
1
What is th regulator series used to get 5v and 1 Amp at its output....if input is 5V

3. ### studiot AAC Fanatic!

Nov 9, 2007
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515
I agree with Nandu, your question is a bit vague,

But, since you have an input and an output perhaps you are not asking about Nandu's answer which does actually has a different input and output voltage.

A simple transistor acts as a current amplifier.

We call the ratio of the output current to the input current the (current) gain or beta.

With suitable circuit arrangements we can arrange for the input and output voltage to be at the same values, whilst the current is increased.

Since power is current times voltage this is also known as a power amplifier and is very familiar in audio engineering.

Integrated circuit chips called Norton amplifiers may also be used to increase the current.

4. ### harikanaidu Thread Starter Member

Nov 28, 2014
76
1
I don't know the component or device to be used....
I have 5V in my circuit with low current...I wan to get same voltage that is 5V with amplified current...How to do this

5. ### studiot AAC Fanatic!

Nov 9, 2007
5,005
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Where does it come from?

Is it a power supply voltage?

Or is it a signal from a digital circuit in the form of 5 volt pulses?

or what?

And secondly what are you going to supply the increased current to?
In other words what is the load?

6. ### harikanaidu Thread Starter Member

Nov 28, 2014
76
1
it is a signal from a digital cirucit

7. ### studiot AAC Fanatic!

Nov 9, 2007
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Digital circuits have a parameter called fan out.

This is the number of digital circuit gates that the output of a particular chip will drive.

To increase this you need to put a digital buffer between the output and input.

You can either do this using one or more spare gates available in most circuit designs or use a dedicated digital buffer chip such as the 7407 or 7417 in TT or 4010 in CMOS.

The buffer will of course require its own power supply which can come from the circuit's supply.

8. ### GopherT AAC Fanatic!

Nov 23, 2012
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What load do you need to drive (number of amps) for the new "amplified" 5 volt driver circuit?
Any other requirements? Switching speed or rise time, ...

If you need a 100 mA, you can do it with a 2N7000 mosfet.
If you need more, there are many other "logic level" mosfet transistors that can switch with your 5v low current signal.

9. ### studiot AAC Fanatic!

Nov 9, 2007
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Yes indeed you can also use a discrete transistor buffer.

10. ### harikanaidu Thread Starter Member

Nov 28, 2014
76
1
Hi,
One of my answered that increasing the current by maintaining constant voltage same as input indicates that power is created so there will be no such thing exist according to law of conservation of energy..........is this true...please help me

11. ### studiot AAC Fanatic!

Nov 9, 2007
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Power is drawn from the power supply by the circuit which controls that power.

Energy conservation is not broken.
In fact we almost never use energy conservation in electronics.

12. ### GopherT AAC Fanatic!

Nov 23, 2012
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If you have a signal from a Microcontroller that is 5 volts and can deliver a maximum of 20 or 30 mA, then the max load is equivalant to 5/0.030 = 166 ohms. Any fewer ohms in that load would draw too much power and damage the Microcontroller.

Now, you mentioned something about a 1 amp at 5 volts. So, you need some type of boost to allow that weak signal to drive bigger loads.
Normally, a logic-level mosfet transistor is used as a switch. The Microcontroller connected to the gate of the mosfet allows the mosfet to drive loads with very low resistance that draw high amperage loads.

If you don't like MOSFETS, then a relay can also be used if the switching speed can be slow.

13. ### WBahn Moderator

Mar 31, 2012
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4,920
It would be very useful if you could describe what you are trying to accomplish instead of phrasing it as some very abstract, generalized question. Often times an abstract question will garner abstract answers that are too generalized to be of much use, while if you just described what you are trying to accomplish, a very simple solution can be found immediately. For instance, if you were to say that you have a 5V output from a digital part that can only deliver 20 mA but you need to use that signal to activate a 5V relay coil that requires 100 mA to operate, then there is an extremely simple solution (a few of them, in fact), whereas if you say that you have a audio output from a portable CD player and you want to use that to drive 12 loudspeakers distributed around a football field, then that is a completely different problem requiring a very different solution.

14. ### wayneh Expert

Sep 9, 2010
12,405
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It is true. There is NO circuit that can increase current at a given voltage without an external power supply. Such a circuit would create power and violate the laws of thermodynamics, which no one has succeeded in doing.

Most or all of the answers here assumed you wanted to increase the power of your signal by controlling a larger power source with that small signal. Almost no one thought you might be searching for the magic circuit that can break the laws of thermodynamics.