OpAmp basics: balanced to unbalanced signal with difference amplifier

RE: OpAmp basics: balanced to unbalanced signal with difference amplifier

jc2048 — Tue, 06 Sep 2022 09:13:17 GMT

Clayton, in Linear Integrated Circuit Applications (1975), gives this for varying the gain of the single amplifier circuit.

He then follows the single-amplifier circuit, in the usual way for these kind of texts, with this two-amplifier circuit.

That circuit can also be adapted for variable gain with a preset between the two inverting inputs.

RE: OpAmp basics: balanced to unbalanced signal with difference amplifier

shabaz — Tue, 06 Sep 2022 00:30:02 GMT

Hi Jan,

Your blog post reminds me of a technique popular with ham radio enthusiasts, who often need to convert from unbalanced to balanced (and vice-versa), but at frequencies from tens of kHz to tens or hundreds of MHz (or higher). They use 'baluns' which get built in different ways depending on the optimal frequency range and power capability. I wrote a draft blog post on them a while back, mainly a lot of theory, but never published it, It had no construction or testing of anything as such since I didn't get around to that. I don't know if it's worth still publishing, although I will not get around to writing up more on that topic for a while due to other stuff getting in the way : (

RE: OpAmp basics: balanced to unbalanced signal with difference amplifier

DAB — Mon, 05 Sep 2022 19:08:08 GMT

Nice blog Jan.

The Appnote was very interesting.