This is an amp that I made to beef up the output of my signal generator. It's DC coupled so there are no phase shifts at low frequencies and it can account for any DC offset applied to the signal. It's very useful for testing resonance, core saturation of transformers and heavy loads.
Link to article: https://www.dmcinfo.com/latest-thinking/blog/id/9462/low-cost-function-generator-amplifier-diy
