RPN-35 SD 2.1

Released on January 4, 1972, the HP-35 from Hewlett-Packard marked a significant milestone as the world's first scientific calculator compact enough to slip into a shirt pocket, specifically Bill Hewlett's. This pioneering device quickly gained popularity among students, engineers, and scientists alike. Despite its substantial price tag of $395 at the time (equivalent to over $2,200 today), the HP-35 exceeded sales projections by tenfold in its inaugural year.

Discover this remarkable calculator, recognized with the esteemed "IEEE Milestone in Electrical Engineering and Computing" award in 2009.

Features:

• Photo-realistic design
• Three available skins: original version 1, versions 2 & 3 (1973), and final iteration version 4 (1974)
• Vintage mode
• Enhanced memory functionality
• Optional key-click and key-glow effects
• Swipe left on the display for correcting erroneous inputs
• Cut/copy/paste the displayed value
• Show stack and memory registers
• Indicator lights for all decimal points remaining illuminated when iPhone battery drops below 5%

Vintage Mode:

In Vintage Mode, users experience authentic features reminiscent of the original HP-35:

• Operation speed mimics the original device
• The Z stack register is copied to T during trigonometric functions
• Entrance of leading zeros is permitted
• Negative numbers input by pressing CHS before or after entering the value
• No stack increment if a keyboard entry or RCL follows STO
• Exclusive arithmetic bugs found only in version 1

Enhanced Memory Mode:

• Non-volatile stack and registers for data retention
• Utilize registers 1 through 9 featuring HP-45-like register arithmetic
• Register 0 acts as a LastX register for added convenience