I have a waveform generator and I would like to take the output and amplify it for input to various types of motors (AC, DC, stepper, etc.) or other gizmos for experiments at the bench at home. I would like to have the amplified voltage variable (set via a dial) up to at least 25 volts with up to 5 amps or so and follow the signal output from the waveform generator (sine, square, triangle, ramps, or whatever I choose to output). I would like frequencies up to around 10 kHz (frequency determined by waveform generator output but up to 10 kHz). The amplifier will be powered by standard 115V 60Hz power. Any ideas on the circuit design of such a device? Specs are somewhat flexible depending on doability/cost. Anything is better than what I have now which is nothing.

 

A 125W mono audio amp designed for a 4Ω load may work for you.
You can use a pot at the amp input to control the output amplitude.
Note that you want one with a non-bridged output, which many car audio amps do have.
You cannot use a grounded load with a bridge amp.

 

I forgot to mention in my original post that I need to go down to DC output so frequency of 0 to 10K Hz.

 

This amp is DC coupled and can deliver up to 7A.
It has inherent protection against shorts and thermal overload.
Note that it will need to be mounted on a good heatsink with thermal grease.
You will need to add the appropriate power supplies of course.

They sell them in kits on Ebay and Amazon.

 

This amp is DC coupled and can deliver up to 7A.
It has inherent protection against shorts and thermal overload.
Note that it will need to be mounted on a good heatsink with thermal grease.
You will need to add the appropriate power supplies of course.

They sell them in kits on Ebay and Amazon.

Thanks

 

Another high power opamp is OPA549.
Drives 8A continuous.
60V max or ±30V.