Calculated Industries

ElectriCalc Pro 5055

Calculated Industries makes special purpose calculators for engineering professionals. This one is for electrical contractors.

Of note, it contains replaceable firmware to adhere to evolving National Electrical Code standards. This early example had to be returned to the manufacturer for upgrade, but later models bore a compartment in the back where a user could insert chips containing new standards.

The Loan Arranger II

I collected this just for the name! Hi-yo, Silver (dollars), away!

This calculator features postfix + and - so

  • A + B + yields A + B. If you try A + B =, it yields 0!

= is reserved for infix * and /, which yield results to 2 decimals and offer constant features:

  • A * B = yields A * B and puts A * into constant memory so pressing C = afterward produces A * C

  • A / B = yields A / B and puts / B into constant memory so pressing C = afterward yields C / B

It offers two loan calculations as described on the back label:

    • calculate monthly PMT from entered loan AMT, INT rate, and TERM in months

    • calculate LOAN from entered monthly payment AMT, INT rate, and TERM in months

In either case you enter the AMT, INT and TERM, and then press LOAN/PMT.

The CH key changes sign, and plays a role in entering INT and TERM, and calculating either LOAN or PMT.

  • Pressing A AMT puts A into AMT

  • Pressing A INT puts A/100 into INT. Pressing A CH INT puts A / (12*100) into INT.

  • Pressing A TERM puts A (months) into TERM. Pressing A CH TERM puts A*12 months into TERM.

  • Pressing LOAN/PMT calculates PMT from AMT, INT and TERM. Pressing CH LOAN/PMT calculates LOAN from AMT, INT and TERM.