Buying an amplifier

[Jacktron]

I am trying to buy an amplifier but I have never bought one before, so I am a little confused. When you buy an amplifier, does it come with the circuit described on the product page. Take this LTC6268 https://www.analog.com/en/products/ltc6268.html#part-details the data sheet that is provided shows the LTC in a circuit, is that circuit inside the chip or do i have to provide those parts myself?

[Manul]

LTC6268 is an Operational Amplifier, or Op Amp for short. Op Amp has power supply pins, inverting (-) and non-inverting (+) input pins and one output pin (there could be two output pins (differential output Op Amp), there could be options like shutdown pin, offset pin, compensation pin, etc). These pins are shown in Op Amp symbol - triangle. Everything around the triangle are separate components, they are not part of Op Amp.

LTC6268 might not be the easiest Op Amp to get started, cause it's fast and requires a fair amount of attention to detail to get the best out of it.

You can sometimes buy evaluation boards which are built to showcase the Op Amp or some other IC. They are fully functional circuits with additional components already selected.

[Jacktron]

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

[Manul]

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

Audio amplifier might suit you. Either home stereo amplifier or some cheap Class-D no-name module. In that case you don't need to build your own, which is a huge time saver.