hp30s

it is apparent that the hp30s is one of hp's attempts to compete in the scientific calculator budget market. build quality is low compared to their older pioneer range like the 20s and 32sii and it does not have that hp feel about it. its a lot cheaper than the older hp offerings. it is manufactured in china by kinpo who also make models for texas instruments. compare it to the ti30xbii.

calculations are formula entry (rpn is long gone). the internal precision is very good. it appears to perform all calculations to 24 digits of precision, but only displays a ten digit answer. this appears true of all scientific functions except for square root. i can only get a 10 digit accurate square root out of the machine which makes the built in square root key less accurate than performing the root using logs!

internally it appears to calculate in binary, this can be verified by multiplying a number repeatedly by 2 and throwing away the integer part. eventually the number sequence will end. not the case if 10 is used. note that almost all other machines internally operate in decimal. it gets tan(355/226) radians correct to 10 digits. see the torture test.

the purple faceplate is removable and you get two other colors in the package for your amusement. in this series is also the 9s and 9g units which are more expensive, but not especially more featured.

i've been trying to fool the internal binary, so far i've revealed this: 2+1e-9-2=0 which it shouldnt be on a 10 digit machine. see also binary calculators.