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I would like to build a low voltage op-amp circuit for an analog computer. Can it be done ? I would like to use tubes in the 12 volt range. The idea is to construct an analog computer like the Heathkit EC-1, but using low voltage tubes for the op-amps. The EC-1 is very expensive, and hard to find on Ebay etc. Any ideas? Thanking you in advance, Wayne Verish


An op-amp is essentially a high-gain differential amplifier, with the gain kept in check by using it within a negative feedback circuit. I can't think of any reason offhand that you couldn't design one around lower-voltage tubes... but my analog design skills, _except_ for op-amp based design, are pretty much gone at this point.

Thanks for your help, and info. best..........................Wayne

I don't know much about tubes, unfortunately, but I would imagine that the schematics only need to be slightly altered for the supply voltage. I do know that most common tubes have low-voltage counterparts with identical (or nearly so) pin-outs.

Thanks for the quick reply and information. Looks like I should keep on saving for an EC-1 computer. best.........Wayne

Op amp schematicusing tubes. They are not low voltage. You will have to pick the tubes you want to use and see if the specs. are close and adjust the circuit.

Good luck.

Thanks for the quick reply, and great schematic link! Best...........Wayne

Here's a link the the EC-1 computer just to get you started if you haven't seen it yet.

Sorry I forgot to save the link and then hurried off to the office.