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I am currently working on a design to generate a 5VAC (rms) @ 400Hz supply capable of 5A continuous. The design contains a non-inverting amplifier that takes a 213mV (rms) @ 400Hz voltage waveform (generated by a COTS board) and boosts it up to 5VAC (rms) @ 400Hz. The circuit is shown below:

OPA541 Non-Inverting Amplifier Circuit

This circuit works just fine, effectively generating the 5VAC output that I desire... that is... until I put it under load... When I connect this thing to our expected load (special incandescent aircraft light-bulb design, the voltage on the output waveform gets sucked down to 3.2VAC (rms) and draws 1.039 Amps AC (rms), and stays at 3.2VAC until I remove the load. When I remove the load, the amplifier output returns to 5VAC @ 400Hz. What could be causing the voltage to get sucked down like this?

Some additional information (not sure whether it will help anyone looking at this, but figured I'd share as much information as I actually understand/know). I've tried a specialized industrial supply capable of 5VAC @ 400Hz (at very high current) and the voltage does not get sucked down at all. Under normal circumstances the bulb draws 1.15 Amps AC (rms) from the industrial supply when 5VAC 400Hz is applied, not impacting the voltage whatsoever. I am convinced there is something wrong with my amplifier circuit...

Let me know if there are any other details that would help if I provided, or am missing something.

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  • \$\begingroup\$ Let us continue this discussion in chat. \$\endgroup\$
    – Snoop
    Feb 5 '18 at 15:41
  • \$\begingroup\$ Comments are not for extended discussion; this conversation has been moved to chat. \$\endgroup\$
    – clabacchio
    Feb 5 '18 at 15:54
  • \$\begingroup\$ @clabacchio Should have moved it to chat sooner, I apologize. \$\endgroup\$
    – Snoop
    Feb 5 '18 at 15:57
  • \$\begingroup\$ No problem, the only thing is that I didn't mean to create a different chat, only I couldn't move the comments to the same you created. I'd say stick to one and use the other as additional material, but if possible get to an answer eventually. \$\endgroup\$
    – clabacchio
    Feb 5 '18 at 16:01

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