dc ampplification

HOw would i amplify a dc current?? cuz i think bjt amplifiers can be used for ac source only. i think so...

There could be a few ways. Do you want to create a single, constant current or do you want it to be more versatile and be able to handle any given dc current? Do you care if the voltage changes when you amplify the current? More details would help.

actually my PCB drill came with an adapter that doesnt give the required current. the drill needs 1A @ 12-18V

as the voltage can vary in that range so a little variation of voltage wouldnt be a problem.

As the adopter provides only 0.3A after sometime the adapter is damaged and the drill stops working. so i want to make a circuitry that would consist of a tranformer to convert 220v to 15V followed by a rectifier. after this i want some constant current source kind of arrangement that would provide 1A of constant current to the drill.

So what you need is a DC converter rather than an amplifier right?

Amplifiers are for working with data-carrying signals rather than power). Amplifiers are use a high power source (that is already there and ready) and use it to make a low power signal more powerful. In your case, what you need IS the high power source to run your drill.

Your adapter can only output a limited amount of power. So if you take the power from the adapter to increase current you will lower the voltage. What you want is same voltage at higher current for your drill. This means your adapter will not work, and you cannot make something to produce more power from your adapter.

You need to have more adapters coming from the wall (the higher power source which has higher voltage and lower current, so you can change it to higher current with lower voltage). Or you need to get a bigger adapter. The adapter you have will not work with the drill no matter what you do.

yup... That would be right. but it should fullfill the current requirement.

I was changing my previous post. So please read it again.

Your adapter will not work no matter what you do, because your drill needs more power than your adapter can give (so it is impossible to increase the current without making the voltage lower). You need a bigger adapter, or you need to use more of them in parallel.

BJTs can amplify a DC and AC signal, but they need to use a high power source already there.

You can't create energy from nothing, get a bigger adaptor with a higher current rating or use a car battery.

You are confusing yourself by your terminology - there is really no such thing as an 'amplifier' - an 'amplifier' merely makes a larger copy of the original signal, it doesn't actually 'amplify' the original at all.

Then how to get rid of the problem?? should i design a transformer again for that purpose?? or what............

give me some solution..

mshemyalnisar said:

Then how to get rid of the problem?? should i design a transformer again for that purpose?? or what............

give me some solution..

Click to expand...

Get a power supply that's suitable, or build one - you can't increase the power available from the existing one without completely rebuilding it (starting with a new transformer).

mshemyalnisar said:

give me some solution..

Click to expand...

We already have, get a more powerful power supply with the rating you need.

mshemyalnisar said:

Then how to get rid of the problem?? should i design a transformer again for that purpose?? or what............

give me some solution..

Click to expand...

You can use an old PC source...can easily deliver 1A @12V (I used one for someting like 8A .....an old 200W at source)

"Energy can neither be created of destroyed"
So use a power supply with higher ratings.

The idea of using the old PC Power supply came to my mind and i infact did open an old PC for the supply. but i dont know how to use it because all the outputs have an IDE-Port.. Can anybody tell me how to get the output from that??