Current

[Jacktron]

How can I convert the amplified voltage here to current? I am trying to create an ac magnetic field using a function generator

[IanB]

Look, I have placed all of your questions in one place for reference.

The truth is that what you are asking about is so far beyond your level of understanding and capability, that even if an answer was provided it would not help you.

The best advice for you is to stop asking about how to generate an AC magnetic field, and instead try explaining what it is you hope to do with it, if somehow you were to succeed?

Tell us your goals. Tell us what problem you are trying to solve?

I am trying to create a circuit that can generates AC magnetic fields in two pairs of helmholtz coils. How can I best do this and could you include schematics from a place like falstad?

I added a little more info: I have two pairs of helmholtz coils that I want to generate ac magnetic fields of for example 0.01 T

one pair with a radius of 2 cm and another with 1 cm

I am trying to create an ac field

10 hertz

20 coils

.1 cm wire

i have 9v dc battery

I need an amplifier that can amplify the signal from a function generator to create an ac electromagnet

I need an amplifier that can amplify the signal from a function generator to create an ac electromagnet

I need an amplifier that can amplify the signal from a function generator to create an ac electromagnetic field in two pairs of helmholtz coils

any suggesetions? preferably something cheap

How can I convert the amplified voltage here to current? I am trying to create an ac magnetic field using a function generator

[magic]

Hmm, let's try.

AC magnetic field + coils + secrecy = over unity

Usually

As for the question at hand, just google "how to do a current source with an opamp". There is a million examples and application notes.

[Andy Chee]

Your project lacks a lot of detail, without detail we cannot give you detailed nor correct advice.

That said, I might begin with a power opamp like the LM1875.  It's cheap enough and should be widely available.

Build your prototype and test it, take some measurements.  And definitely let us know if it blows up!

[Simon]

How can I convert the amplified voltage here to current? I am trying to create an ac magnetic field using a function generator

The amplified voltage where ? One look at your schematic tells me that either you have absolutely no clue to the point that you cannot light a light bulb with a battery if you tried so why on earth are you using all those complicated components or you are a batshit crazy conspiracy theorist, and no I have not read any of your other posts that people here allude to.

Cease this crap or you will be banned!

[PGPG]

How can I convert the amplified voltage here to current?

If you want to convert known voltage (V) into proportional to this voltage current (I) then you use resistor (R).
The relation between these values is given by V = I x R.
Selecting R (resistor resistance) you decide what is the proportionality factor between your voltage and current.

[Simon]

Don't bother wasting your time. Have you seen his circuit? no current flows so the question is mute!

[Zero999]

There needs to be a power supply. Presumably the op-amp's model has one built-in, but the collector of the transistor needs power.

Here's an example of a current sink. It demonstrates the fact the op-amp can run off a lower voltage, than the LEDs. A linear regulator such as the LM317L can be used to power the op-amp.

[Simon]

why are you feeding the troll? As I said they appear to not understand that any current flows only if there are 2 connections, that is why I said they probably can't light a light bulb. If they can light a light bulb then they are taking the piss with that diagram.

[Zero999]

Sorry. I didn't realise posting a constant current sink was against the rules. . .

In all honesty, I just wanted to upload that circuit, so I can use it in other posts and that someone else might find it useful. Other people will read this, than the original poster.

[Simon]

fair enough, I think this one has given up anyway.