a non-HP RPN calculator


In addition to collect HP calculators I decided to collect calculators made in my country Argentina. Of these I have models of the brands: microcifra, Magiclick and Norman.

Yesterday I buyed a "new" one: "microcifra 10" a scientific model that operates what I think is true RPN. It has an [E] (enter) key. It has a stack that can have up to 3 levels, a [x<>y] key and two erase keys:

[C] that acts as "drop": if you enter [1],[E],[2],[E],[3],[C] then you have only two levels ("2" is displayed) and if you press [C] again you have only one level ("1" is displayed).

[C*] erases all the stack. Then all you have is "0" in the first level (and the other two levels doesn´t exist). It also clear the memory register.

The calculator operates on 6 AA bateries and have a 8 digit led display.

You can see it in my site:

I don´t know if this could be interesting in this forum but I couldn´t resist to share.



does anyone know of any other non-hp rpn calculators?


I suspect that there are several non-HP calculators that use RPN. I have one by Omron, model 12SR. It is scientific and has a 4-level stack. The display looks like vacuum florescent. It is larger than most HPs and the manual appears to be dated 1976.


Have a look at this URL:

Non-HP RPN Calculators


that list is good, I don't think it is exhaustive. I know there is at least one heathkit RPN (IIRC, it had a 5 level stack)

This also depends on how far you go in deciding what is RPN. is a ti59 (or ti89) with an rpn program a non-hp rpn?


We had a thread running on this topic not long ago:




I assume this model has been manufactured by National Semiconductor (also known as Novus) - or at least uses NS parts.
The design is very similar to other calculaltors made by them.

If it is (you would have to open it up), it is not considered a real RPN calculator, rather it is an approach to create a cheaper calculator with less logic.

A simpler model, with pseudo-RPN is this one:


many people would agree with you that the novus 650 in the web address you gave is not an rpn. as i remember; dave hicks once said that a 2 level stack is not true rpn. thats big guns on your side. i may be thick but i think that it is just rpn without a stack.

the microcifra that sr. castares was talking about is a novus mathmatician 4510 "calculator on a chip" in a made-in-argintina body. it is very definatly rpn, has a three level stack and novus had a programmable version too. it had no replicating t register but was more hp-like in operation than hp's first three calculators.

as far as we know; lukasiewicz would have prefered 3 or even 2 level stack type calcs to what we like to use and he might have called everything hp made after the 9810 a "psudo rpn". for me: if i stroke 2 enter 3 + and get 5 then it is rpn.

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